Phrasing in prelinguistic vocalizations

Phrasing in Prelinguistic Vocalizations MICHAEL P. LYNCH Department of Audiology & Speech Sciences Purdue University West Lafnyette, Indiana

D. KIMBROUGH OLLER Departments of Psychology, Pediatrics, & Otolaryngology University of Miami Miami, Florida

MICHELE L. STEFFENS Departments of Psychology & Pediatrics University of Miami Miami, Florida

EUGENE H. BUDER Department of Speech & Hearing Sciences University of Washington Seattle, Washington

Phrasing is a universal characteristic of human communication, and the present investigation explored its developmental roots in nonvegetative, prelinguistic vocalizations. Adult judges identified a hierarchical arrangement of syllables embedded within utterances and utterances embedded within prelinguistic phrases in the vocalizations of infants. Prelinguistic phrases were characterized by systematic lengthening of phrase final syllables, temporal patterning, and stable durations across development that were similar to those of some cross-culturally optimal rhythmic units from other domains. Analyses of vocalizations of infants with Down syndrome indicated similar internal structure of prelinguistic phrases to those of typically developing infants, but with longer durations. These findings suggest that relative durational characteristics of prelinguistic phrasing are stable features of early vocal behavior, although the absolute durational characteristics of prelinguistic phrases can be impacted by a complex and severe disorder such as Down syndrome. 0 1995 John Wiley & Sons, Inc.

Reprint requests should be sent to Michael P. Lynch, Department of Audiology and Speech Sciences, 1353 Heavilon Hall, Purdue University, West Lafayette, IN 47907-1353, U.S.A.

Received for publication 1 1 May 1994 Revised for publication 25 July 1994 Accepted for publication 8 August 1994

Developmental Psychobiology 28(1):3-25 (1995) 0 1995 by John Wiley & Sons, Inc. CCC 0012-1630/95/010003-23

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Speech is punctuated by pauses, intonation contours, loudness contours, and stress, which lend to its grouping into phrases (Chomsky & Halle, 1968; Cruttenden, 1986; Crystal, 1969; Pike, 1945). Considerable progress has been made in our understanding of human parsing of serial information (e.g., see Evans & Clynes, 1986; Poppel, 1985). and much of this research suggests that our processing of grouped structures is related to basic functional capabilities, such as those of language (Martin, 1972; Shaffer, 1982; Turner, 1985), auditory processing (e.g., Bower, 1970; Bower & Winzenz, 1969; Dow- ling, 1973; Sturges & Martin, 1974), and visual identification of objects (Rock & Palmer, 1990). Research on motor activity has also suggested that movement can be understood according to general principles of pattern formation and nonlinear dynamics (e.g., Gentner, 1987; Lockman & Thelen, 1993; Turvey & Fitzpatrick, 1993). In the case of speech, perceptual development and feedback about production may serve to modify speech-motor activity toward language-specific action (Thelen, 1991).

Prelinguistic vocalizations provide a unique window on fundamental tendencies of human grouping of serial events because they are precursors of spoken language but are not bounded by linguistic structure. Once rhythmic characteristics of infant sounds are understood, they might offer reference points for origins of prosody in mature language, provide insights about characteristics of the infant’s social microenvironment that may influence the development of hierarchical vocal patterns, and enhance our knowledge of the phylogenetic significance of rhythmic structures that occur across domains and species. Attainment of these clarifications may be facilitated by the study of both typical and disordered infants because characteristics of speech that are retained in the context of a severe disorder could be hypothesized as essential aspects of the speech signal. In the present study, vocalizations of typically developing infants and infants with Down syndrome were compared because infants with Down syndrome are significantly delayed in motor, cognitive, and speech development, thus providing a potentially strong test of the robustness of speech signal characteristics.

Phrasing in Speech Phrasing in speech is constrained by physical and cognitive factors. Respiration

imposes the obvious requirement on speakers to intermittently pause. Independent of respiration, however, pauses sometimes occur in locations that may facilitate language processing, and speakers occasionally insert pauses in discourse without taking a breath. Prosody, which refers to the intonational and rhythmic characteristics of speech, influences productive segmentation of the speech stream. Although prosody interacts with linguistic structure, even in song (Palmer & Kelly, 1992), prosodic phrases in conversa- tion do not always agree with syntactic phrase boundaries. This circumstance seems to hold for infant-directed speech (Fernald & McRoberts, in press), which is linguisti- cally simplified and prosodically exaggerated, and also in infants’ perception of phrasing in speech (Gerken, Jusczyk, & Mandel, 1994). A number of proposals have been offered to account for relations between prosody and syntax (e.g., Beckman & Pierrehumbert, 1986; Cooper & Paccia-Cooper, 1980; Gee & Grosjean, 1983; Ladd, 1986; Ladd & Campbell, 1991; Liberman & Prince, 1977; Morgan, 1986; Nespor & Vogel, 1983, 1986; Price, Ostendorf, Shattuck-Hufnagel, & Fong, 1991; Selkirk, 1980, 1984). Although these proposals vary in many respects, they generally agree that there is a prosodic hierarchy in speech, which will now be very briefly described.

In adult speech, syllables are embedded within prosodic words, which often, although not necessarily (Booij, 19831, correspond to lexical words. Prosodic words are

PRELINGUISTIC PHRASING 5

embedded within intonational phrases, which have cohesive internal structure and are bounded by, among other possibilities, pauses or boundary tones (see Halliday, 1967 for “tone group” description; Lieberman, 1967 for “breath group” description). Some authors have proposed a level between the prosodic word and the intonational phrase. For example, Beckman and Pierrehumbert (1986) and Nespor and Vogel(l986) focus on the “phonological phrase,” which is thought to be signaled by a pitch accent that involves an abrupt loudness increase, pitch increase, or a combination of the two, resulting in prominence for a particular syllable in a sequence of prosodic words.

In prelinguistic vocalizations, human infants begin producing well-formed, “canonical” syllables (Oller, 1986; Oller & Lynch, 1992) during the latter half of the first year of life. These syllables consist of a closant (consonant-like element) and a vocant (vowel- like element) with a closant-vocant or vocant-closant transition that has a duration that commonly occurs in natural spoken languages (generally < 120 ms). Thus, canonical syllables are the syllabic foundations of words produced later in development. Prelin- guistic infants also produce other syllable types, as well (see Oller & Lynch, 1992 for descriptions), and these syllables (including canonical syllables) have generally been studied within the context of the “utterance,” which is usually bounded by either audible ingressive breaths or silences that are 1 s in duration (Stark, 1980; Lynch, Oller, & Steffens, 1989). The construct referred to by use of the term utterance in the study of prelinguistic vocalizations is in some ways more specific than the various constructs that have been referred to using the same term in description of adult speech, such as adult vocalizations which might be as short as a word or as long as a sentence (Crutten- den, 1986, p. 1).

Phrasing Across Domains and Species As described in the previous section, speech phrasing is hierarchical. Hierarchical

rhythmic organization has also been documented in other domains, such as in music and spoken poetry. In music, individual notes are embedded in groupings referred to as figures, which are embedded in phrases (Lerdahl & Jackendoff, 1983). The musical note is analogous to the syllable in its status as a minimal rhythmic unit, and the musical figure is analogous to either the prosodic word or phonological phrase in its intermediate status between minimal rhythmic units and phrases. Musical phrases are similar to speech phrases in marking of phrase boundaries (e.g., phrase final lengthening; Lind- blom, 1978), and poetry is organized with an ascending hierarchy of rhythmic embeddedness, from the syllable, to the foot (analogous to musical figures, phonological phrases, and prosodic words), to the line (analogous to phrases in speech and music) (Poppel, 1985; Turner, 1985).

Hierarchical rhythmic structure is not limited to the auditory domain, as evidenced by studies of sign languages (e.g., Grosjean & Lane, 1981; Wilbur, 1993; Wilbur & Nolan, 1986), nor is it unique to human communication. Fentress and colleagues (Fen- tress, 1989; Fentress & Stillwell, 1973) have described hierarchical grammatical structure in the facial grooming movements of mice, including bout final lengthening of grooming movements, and recent evidence has pointed to neuronal coding of rat grooming patterns (Aldrige, Berridge, Herman, & Zimmer, 1993). Tyack and colleagues have outlined a hierarchical phrase structure of songs of humpback whales (Payne, Tyack, & Payne, 1984; Tyack, 1986), and fin whales have been documented to group their low- frequency vocalizations in pulse trains, the temporal patterns of which differentiate fin whales according to Atlantic and Pacific regions (Thompson, Findley, & Vidal, 1992).

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In addition, Hauser and Fowler (1992) found that both vervet monkeys and rhesus macaques had reliable pitch falls at the ends of their utterances. It is possible that hierarchical communicative parsing is common to many species, either because of biological commonalities or possible consistencies in rearing practices (e .g., involving caregiver-infant interaction) and environments (Cynx, 1990; Marler & Sherman, 1983, 1985).

Human Infants If a rhythmic hierarchy of grouping units is present in early human vocalizations,

then it may serve as a set of frames into which lexical and syntactic units can be assimilated (MacNeilage & Davis, 1990; Papousek, Papousek, & Bornstein, 1985). The notion of early prosody in language input providing a basis for language development has received significant research attention (e.g., Fernald & Morikawa, 1993; Morgan, 1986), but the focus of this work has been either on infant-directed speech of adults (i.e., “motherese”) or on infant perception. Very little research has been conducted on the phrasal structure of vocalizations produced by infants.

In studies of infant perception (Hirsh-Pasek, et al., 1987; Jusczyk et al., 1992; Kemler Nelson, Hirsh-Pasek, Jusczyk & Wright-Cassidy, 1989), the duration of infants’ visual fixation toward a loudspeaker that presented running speech was measured. One- second pauses were inserted at grammatically appropriate and inappropriate locations. The infants gazed for longer time periods toward well-phrased speech than toward poorly phrased speech. With variation in ages at which effects were observed, analogous results have been obtained with musical stimuli (Asgari, Pinto, & Fernald. 1993; Jusczyk & Krumhansl, in press: Krumhansl & Jusczyk, 1990).

Infants’ perception of phrasing in both speech and music suggests that general, rather than language-specific, processes may be implicated. In light of infant responses to the special characteristics of infant-directed speech (e.g., Fernald & Kuhl, 1987; Papousek, Bornstein, Nuzzo, Papousek, & Symmes, 1990), it is possible that a hierarchy of grouping structures may be important in human vocal development.

In the study of speech and language development, there is general agreement that early identification is critical to our basic knowledge of disorders. In particular, language delay is well documented and severe for children with Down syndrome (Miller, 1988). Until recently, the earliest deviance from typical development in speech of infants with Down syndrome was documented in the second year of life (e.g., Cardoso-Martins, Mervis, & Mervis, 1985; Smith & von Tetzchner, 1986; Van Borsel, 1988). We now know, however, that infants with Down syndrome begin production of canonical, speech-like syllables an average of 2 months later (at 9 months) than typically developing infants (at 7 months) (Lynch et al., in press). In addition, infants with Down syndrome are delayed in motor development (Butterworth & Cicchetti, 1978) and have disordered anatomical development (Ardran, Harker, & Kemp, 1972; Farkas, Munro, & Kolar, 1985; Fink, Madaus, & Walker, 1975; Frostad, Cleall, & Melosky, 1971; Wahrman & Fried, 1970). The complex phenotype of Down syndrome in domains related to vocal production thus suggests that temporal characteristics of prelinguistic phrases of infants with Down syndrome may differ from those of typically developing infants and makes these infants a potentially robust comparison group for study of typical development of speech phrasing.


Empirical Questions Answers to three questions were pursued in the present study: (a) Are there prelin-

guistic phrases?; (b) if there are prelinguistic phrases, do they have quantifiable structural cohesiveness like that of phrases in adult speech?; and (c) if there are prelinguistic phrases, are their characteristics affected by Down syndrome, a complex disorder involving motoric and cognitive factors that has been associated with marked speech and language delay in childhood?

Although the ability of adult listeners to recognize prosodic groupings in infants has not been directly addressed, previous research has assumed the existence of at least two levels of rhythmic grouping in infant vocalizations. The syllable has been treated as the minimal rhythmic unit, and the utterance (also commonly termed “breath group,” Stark, 1980) as the maximal rhythmic unit. As a methodological necessity, the infant vocal stream has been divided into utterances, which are typically bounded by ingressive breaths, so that the developmental status of syllables could be documented. The characteristics of infant vocalizations that make such parsing of the vocal stream possible, however, have not been studied in detail (de Boysson-Bardies, Sagart, & Durand, 1984; Kent, Mitchell, & Sancier, 1991). The present study involved employment of adult judges in parsing of the infant vocal stream, and the temporal characteristics of this parsing were studied.

One important temporal characteristic of speech is lengthening of the final syllable or vowel of a rhythmic unit (e.g., Fonagy & Magdics, 1960; Klatt, 1975; Lindblom, 1978; Oller, 1973; Scott, 1982; Wightman, Shattuck-Hufnagel, Ostendorf, & Price, 1992). Perception of final syllable lengthening has been proposed to account for the phrasing perception of English-learning infants (Jusczyk et al., 1992) and children (Beach et al., 1991). Jusczyk and Krumhansl (in press) also suggested that lengthened final- note durations may contribute to infants’ perception of phrasing in music.

There is controversy about the development of production of final-lengthening in speech. In studies of infants, some investigators have reported the occurrence of final- lengthening (Blackwell, 1991; Levitt & Utman, 1992; Levitt & Wang, 1991; Robb & Saxman, 1990; Zlatin-Laufer, 1980), but others have not (Oller & Smith, 1977). Although not tested directly, a plausible explanation for the discrepant findings is that the different vocal units in which final lengthening has been studied in infants could account for the different findings. For example, Blackwell (1991) studied final lengthening in disyllables (e.g., “baba” and “mama”), but Oller and Smith (1977) studied final lengthening in reduplicated babbling (e.g., repeated sequences of two-six syllables such as “dada,” “bababa,” “ mamamamamama”). Controversy also exists as a result of studies of older children. Allen (1983) found some indication of final vowel lengthening in polysyllabic words uttered in a picture identification task by French-speaking 2-year-olds, and Snow (1992) found lengthening of final vowels in spontaneous two-word utterances of English- speaking 2-year-olds. Konopczynski (1986), however, did not find such effects in spontaneous vocalizations of French-learning children.

The present study addressed in a new light the possible role of final lengthening in prelinguistic vocalizations. In previous studies, infants’ utterances were selected for final syllable analysis based on their conformity to particular syllabic or segmental characteristics and consequently may not have addressed the possible global role of final syllable lengthening in boundary marking. For example, these studies often required syllables to consist of consonant-vowel (CV) structure or to contain specific types of consonants, such as bilabial stops (e.g., as in the syllable [ba]). In the present work, final syllable lengthening was analyzed in all nonvegetative sounds produced by infant subjects from 2-12 months of age.

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Another important temporal characteristic of adult speech is the tendency for rhythmic unit durations to become compressed when embedded in higher-order rhythmic units. This phenomenon occurs in syllables with increases in the number of syllables per utterance (Malecot, Johnston, & Kizziar, 1972) and in segment durations with increases in the numbers of segments in syllables, words, or phrases (Lindblom & Rapp, 1973; Lyberg, 1977; Strangert, 1978). Compression of rhythmic unit durations within higher-order units has also been noted in nonspeech domains of human movement, such as juggling (Beek & Turvey, 1992; Beek & van Santvoord, 1992) and piano playing (Shaffer, Clarke, & Todd, 1985). Several proposals have been offered to account for this phenomenon, including lexico-syntactic planning (Darwin, 1975; Kohler, 1983; Martin, 1975; Nooteboom & Cohen, 1975; Wingfield, 1975) and generalized motor programs that maintain invariant durational relations among rhythmic units (Gentner, 1987). In the present study, rhythmic unit compression was studied without influence of linguistic structure, thus some light may be shed on issues of planning versus generalized motor programs.

Previous work has indicated that disorders can affect vocal development in infants. For example, audition is critical for timely onset of well-formed syllable production, which occurs prior to 11 months of age under typical circumstances, but is significantly delayed in deaf infants (Lynch et a]., 1989; Oller, Eilers, Bull, & Carney, 1985; Oller & Eilers, 1988). The onset of well-formed syllable production is also delayed in infants with Down syndrome (Lynch et al., in press). Comparison of phrasing characteristics of infants with Down syndrome with those of typically developing infants may show differences in speech production between these groups at earlier ages than have been found in previous work (see Lynch & Eilers, 1991; Lynch et al., in press; Miller, 1988), as may be reasonably hypothesized in light of the complex delays observed in infants with Down syndrome in domains related to vocal production (e.g., motor development; see Nadel, 1988 for reviews).

Met hods

Subjects Eight typically developing infants and 8 infants with Down syndrome were longitudi-

nally studied from 2 to 12 months of age. The typically developing infants were healthy and free of birth complications. The health of the infants with Down syndrome was generally good, and health status has not been found to significantly affect prelinguistic vocal development or the development of meaningful speech of infants or children with Down syndrome (Lynch et al., in press; Miller, 1988). Two of the infants with Down syndrome were premature (less than 37 weeks gestational age and less than 2500 g birthweight), and their ages were corrected for gestation before entry of data into analyses. The hearing of infants in both groups was screened at 500 Hz, 1000 Hz, 2000 Hz, and 4000 Hz using computer-controlled visually reinforced audiometry (Eilers, Widen, Urbano, Hudson, & Gonzales, 1991; Ozdamar, Eilers, Miskiel, &Widen, 1990) and standard typanometry. The hearing levels and tympanograms of the typically developing infants and infants with Down syndrome were within normal parameters.

Recording Environment Procedure Monthly audiotape recordings were made of the infants’ vocalizations in a sound-

controlled chamber that housed a bed, a box of quiet toys, and recording equipment (Marantz PMD-221 audiocassette recorder and Bose PM-10 external microphone). Pres-


ent in the recording sessions were the infant, one parent (usually the mother), and a laboratory assistant. The recording procedure was flexible within the space constraints of the recording chamber and the need to have the microphone within a reasonable distance of the child’s mouth to ensure good recording fidelity. During sessions, infants were allowed to move freely within the chamber and were provided with toys. Parents sometimes played with the infants, engaged in face-to-face interaction with the infants, or conversed with the recording assistant. The recording assistant also sometimes engaged infants in play or face-to-face interaction. In order to avoid obscuring the infants’ voice as recorded on tape, adults to the extent possible refrained from talking while the infants were vocalizing. Sessions generally lasted 20 min, and subjects were reimbursed for their participation.

Analysis of Infant Vocalizations In order to optimize stability of data and reduce measurement error, data were

aggregated across 2- to 4-, 6- to 8-, and 10- to 12-month samples (Epstein, 1980; Wachs, 1991). The audiotapes of the infants’ vocalizations were analyzed in three phases. In Phase 1 , nonvegetative utterances were identified by trained adult judges. Nonvegetative sounds are vocalizations without any connection to obvious biological function (e.g., cough, sneeze) or physical state (e.g., cry, laugh). These types of utterances (including categories generally referred to as “babbling,” “cooing,” etc.) have been analyzed in a number of previous studies (e.g., Oller 22 Eilers, 1988). Utterances have been the most commonly used analysis units in studies of infant vocal production, and are generally bounded by either audible ingressive breaths or 1 s of silence (Lynch et al., 1989). Utterances were coded in sequence with the counter numbers that corresponded to their locations on the tape. A printout showing these tape counter numbers, the types of syllables contained in each utterance, and the number of syllables in each utterance was generated and used in Phase 2 of the analysis.

In Phase 2, an adult English-speaking listener with no special training in coding of infant vocalizations, prosody, or recognition of rhythm was presented with the utterance printouts and instructed to indicate which utterances “went together” by bracketing the utterances on the printout while listening to the corresponding recordings. Thus, the judge performed the bracketings with knowledge of the temporal locations of utterances on the tape, the syllabic content of the utterances, as well as the number of syllables in the utterances, all of which were provided from the printouts. Six additional, untrained observers judged randomly selected samples (10% of the original corpus) in order to check the reliability of the primary judge’s bracketings. The utterances that were bracketed together in this stage of the analysis formed groups that were subsequently considered to be prelinguistic phrases.

In Phase 3 of the analysis, the durations of all syllables, utterances, and prelinguistic phrases were measured. All silences between and within these rhythmic units were also measured with a Kay 5500 real-time DSP sonagraph (300-Hz analysis filter). Rhyth- mic unit boundaries were generally recognizable from wide-band spectrograms, but when they were not an amplitude display was used to aid the determination of onsets and offsets of vocal activity. As in Phase 2 of the analysis, the experimenter had available the printout for each sample that showed the location and characteristics of each syllable, utterance, and prelinguistic phrase. In the acoustical analysis, syllables were identified as occurrences of pronounced acoustic energy that were generally less than 500 ms in duration on the spectrograms and amplitude displays. The corresponding

10 LYNCH ET AL.

perceptual characteristics were the presence of either a nucleus in isolation (e.g., vowel- like sound without accompanying consonant-like component) or a closant (consonant- like sound) and nucleus together in sequence, with either segment occurring first in the syllable (see Oller, 1986; Oller & Lynch, 1992 for acoustic-perceptual definitions of infant syllables). Utterances were sometimes monosyllabic, but when they were polysyllabic they were identified by the number of syllables evident. Prelinguistic phrases always contained more than one utterance and were identified according to the syllabic content of their utterances. Using the printouts of the adult judges’ identifications of the syllables, utterances, and prelinguistic phrases, the experimenter was readily able to locate the relevant units for measurement.

Results

Question 1 : Are There Prelinguistic Phrases? The primary evidence of the existence of prelinguistic phrases was that, without

training, adult judges were able to reliably identify phrases through listening when given information on printouts about the syllables and utterances in the infants’ samples. In an analysis of the reliability of identification of prelinguistic phrases in the 10% of randomly selected samples that were coded by additional judges in Phase 2 of the analysis, the average agreement between the secondary judges and the primary judge was 0.88 (Cohen’s Kappa). On average, slightly more than half of the 70 utterances in each sample were judged to be embedded within prelinguistic phrases (59%), and all samples contained at least 10 prelinguistic phrases. In an analysis of the reliability of location of rhythmic units during acoustic analysis in Phase 3 of the overall analysis, two judges independently determined rhythmic unit locations in 10 randomly selected samples, and their agreement was 0.82 (Cohen’s Kappa).

Question 2: Do Prelinguistic Phrases Have Quantifiable Structural Cohesiveness? The durations of utterance final and phrase final syllables were compared with

nonfinal syllables in the same rhythmic units. Because some utterances were embedded within designated prelinguistic phrses and some utterances were not embedded within phrases, utterance final lengthening effects were examined separately for these two types of utterances.

For both utterance types, 3 X 2 (Age X Syllable Position: Final vs. Nonfinal) analyses of variance (ANOVAs) were conducted. Neither analysis revealed statistically reliable syllable-position effects or interactions with that factor (syllable-position effect for utterances embedded within phrases, F(1,14) = 1.8, p < .202; syllable-position effect for utterances not embedded within phrases, F( 1,14) = 0.4, p < .549). Therefore, final lengthening was not characteristic of utterance endings.

To examine whether final lengthening was characteristic of prelinguistic phrase endings, a 3 x 2 (Age X Syllable Position: Final vs. Nonfinal) ANOVA was conducted and revealed statistically reliable main effects of age, F(2,28) = 5 . 4 ~ < .01, and syllable position, F(1,14) = 9.2, p < .009. The Age X Syllable Position interaction was not statistically reliable, F(2,28) = 1.5, p < .241. Post-hoc 1 tests indicated that phrase- final syllables were reliably longer than nonfinal syllables were at 2-4 months, t(14) =

0.6

0'7 I PRELINGUISTIC PHRASING 11

T

0.3 i I

Non-Final Syllables

1

I I

6-8 10-12

Age (months)

Fig. 1. Typically developing infants' phase final-syllable lengthening. Filled circles indicate data for phrase final syllables. Open circles indicate data for all nonfinal syllables within phrases. Durations are expressed in seconds. Error bars = 95% confidence interval.

3.5, p < .004, and at 10-12 months, t(14) = 2.9, p < .012), but not at 6-8 months, t(14) = 1.3, p < .211. These data are depicted in Figure 1.

One indication of internal structure of prelinguistic phrses may be systematic compression of syllable durations according to their embeddedness. Overall durations were compared for syllables embedded in prelinguistic phrases and syllables not embedded inprelinguistic phrases. In a 3 x 2 (Age x Syllable Status: Embedded vs. Not Embedded) ANOVA, neither the syllable status main effect, F(1,14) = 1.1, p < .313, nor the interaction were statistically reliable, suggesting that syllables were not globally compressed as a function of phrase embeddedness.

Another broad comparison was made between utterances embedded within prelinguistic phrases and utterances not embedded within prelinguistic phrases. In a 3 X 2 (Age X Utterance Status: Embedded vs. Not Embedded)'ANOVA, neither the utterance status main effect, F(I ,14) = 0.7, p < .411, nor the interaction were statistically reliable, suggesting that utterances were not globally compressed within prelinguistic phrases.

Utterance embeddedness was also examined for syllables. In this assessment, syllable durations of monosyllabic and multisyllabic utterances were compared, both when the utterances were embedded within prelinguistic phrases and when they were not embedded within phrases. When utterances were nut embedded within prelinguistic phrases, a 3 x 2 (Age x Syllable Status: in monosyllabic utterance versus in multisyllabic utterance) ANOVA revealed a statistically reliable main effect of syllable status, F(I ,14) = 12.0, p < .004. Post-hoc t tests of syllable status durations at each age, however, revealed no reliable effects at individual age points (All t tests resulted in at least p < .055). Examination of Figure 2 shows that the lack of statistically reliable t tests was associated with high intersubject variability in monosyllabic utterance durations from 6-12 months of age and with a small mean difference at 2-4 months of age.

When utterances were embedded within prelinguistic phrases, a 3 X 2 (Age X

Syllable Status: in monosyllabic utterance versus in multisyllabic utterance) ANOVA also revealed a statistically reliable main effect of syllable status, F(1,14) = 18.4, p <

12 LYNCH ET AL.

v Syllables in C Monosyllabic 2 0.4 Utterances E

Syllables in Multisyllabic Utterances

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2-4 6-8 10-12

Age (months)

Fig. 2. Typically developing infants’ compression of syllable durations in nonphrased utterances. Filled circles indicate data for syllables in monosyllabic utterances (i.e., syllables produced in isolation). Open circles indicate data for all component syllables of multisyllabic utterances. Durations are expresqed in seconds. Error bars = 95% confidence intervals.

.001. Post-hoc t tests revealed that monosyllabic utterances were reliably longer than the syllables of multisyllabic utterances at 2-4 months, t(14) = 4.5, p < .0001, 6-8 months, (14) = 2.2, p < .049, and 10-12 months, t(14) = 2.8, p < .015 of age. These data are shown in Figure 3.

The results of the post-hoc t tests suggested that compression of syllable durations within utterances appeared to be more well-defined when utterances were embedded

1

Syllables in Multisyllabic Utterances

Age (months)

Fig. 3. Typically developing infants’ compression of syllable durations in phrased utterances. Filled circles indicate data for syllables in monosyllabic utterances embedded in prelinguistic phrases. Open circles indicate data for component syllables of multisyllabic utterances embedded in prelinguistic phrases. Durations are expressed in seconds. Error bars = 95% confidence intervals.


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0.100

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Syllables in Multisyllabic

Utterances

Utterances

Fig. 4. Typically developing infants’ durations of nonphrased syllables, utterances, and corresponding silences between spoken units and next nonvegetative vocalizations. Durations are expressed in seconds on common logarithmic scale. Error bars = + 1 standard deviation. Log scale was employed so that the wide range of values could be shown.

within phrases than when they were not. This finding provides some additional support for the hypothesis that prelinguistic phrases have structural cohesiveness.

Another aspect of cohesion in prelinguistic phrases is correspondence between the durations of spoken units and silences. The durations of each of the three present rhythmic units were compared with silences on their respective levels of the rhythmic hierarchy. Figure 4 shows that the durations of syllables in multisyllabic, nonphrased utterances were similar to those of the intersyllable silences within multisyllabic, nonphrased utterances (as indicated by overlapping standard deviations and means). Non- phrased utterance durations were considerably shorter than the silences between them and the next nonvegetative vocalization.

Figure 5 shows that, within prelinguistic phrases, syllable durations and intersyllable silence durations within utterances were similar. In addition, utterance durations and interutterance silence durations were considerably more similar than when they were not embedded within prelinguistic phrases. Prelinguistic phrase durations, however, were considerably shorter than the silences between them and the next nonvegetative vocalization. Thus, for both nonphrased and phrased vocalizations, when rhythmic units were embedded within higher-order units, their durations were more similar to corresponding silences than when they were not embedded within higher-order units. This pattern suggests durational cohesion of rhythmic units within the three-tier rhythmic hierarchy.

Question 3: Are Prelinguistic Phrases Affected by Down Syndrome?

Overall Durations and Variability In the analysis of syllable durations, a 2 X 3 (Group X Age) ANOVA revealed

statistically reliable main effects of both group, F(1,14) = 12.3, p < .004, and age, F(2,28) = 12.6, p < .0001. A reliable Group X Age interaction was also found, F(2,28

14 LYNCH ET AL.

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Multisyllabic Utterances

Fig. S. Typically developing infants’ durations of phrased rhythmic units and corresponding silences between spoken units and next nonvegetative vocalizations. Durations are expressed in seconds on common logarithmic scale. Error bars = + I standard deviation. Log scale was employed so that the wide range of values could be shown.

= 5.7, p < .008. Figure 6 shows that the interaction can be attributed to a substantial peak in syllable durations for the infants with Down syndrome at 6-8 months of age, and post-hoc t tests revealed that the syllable durations of the infants with Down syndrome were reliably longer than those of the typically developing infants only at 6-8 months, t(7) = 3.2, p < .012, and 10-12 months, t(7) = 2.8, p < . O S . The infant groups were not statistically different at 2-4 months, t(7) = 1.5, p < .17. In the analysis of utterance durations, a 2 x 3 (Group X Age) ANOVA revealed statistically reliable main effects of group, F(1,14) = 7.9, p < .014, and age, F(2,28) = 6.7, p < .004. The Age x Group interaction was not statistically reliable, F(2,28) = 2.0, p < .15. The utterance durations of the infants with Down syndrome, M = 960 ms, SD = 415 ms, were reliably longer overall than those of the typically developing infants, M = 640 ms, SD = 179 ms. In the analysis of prelinguistic phrase durations, a 2 x 3 (Group x Age) ANOVA revealed only a statistically reliable main effect of group, F(1,14) = 14.5, p < .002. The prelinguistic phrases of the infants with Down syndrome, M = 5.3 s, SD = 1.5 s, were reliably longer overall than those of the typically developing infants, M = 3.7 s, SD = 0.66 S.

In order to ascertain whether utterances and prelinguistic phrases of the infants with Down syndrome were longer than those of the typically developing infants simply because of elongated syllables, the durations of all silences within multisyllabic utterances and within prelinguistic phrases were compared between the groups. In the analysis of silences within prelinguistic phrases, a 2 x 3 (Group x Age) ANOVA revealed a main effect of group, F( 1,14) = 2.51, p < .05, indicating that the intraphrase silences of the infants with Down syndrome, M = 960 ms, were reliably longer than those of the typically developing infants, M = 775 ms. No statistically reliable effects were found in the utterance analysis. Therefore, infants with Down syndrome had longer utterances than typically developing infants because of longer syllables, but infants with Down syndrome had longer prelinguistic phrases than typically developing


1.5

1.4

1.3

1.2

1.1

1.0

0.9

-

~

-

- -

-

-

I I

6-8 10-12

Age (months)

Fig. 6. Syllable durations of typically developing infants (filled circles) and infants with Down syndrome (open circles). Durations are expressed in seconds. Error bars = 95% confidence intervals.

infants both because of longer syllables and elongated intersyllabic silences. This sup- ports a proposal that the phrase as a hypothetical communicative timing window may be longer for infants with Down syndrome than for typically developing infants.

In an analysis of variability in syllable durations, each infant’s standard deviation of syllable durations was entered into a 2 X 3 (Group x Age) ANOVA. Smith (1992, in press) has provided evidence indicating that young children’s durations and standard deviations in segmental production are relatively independent measures and that use of duration and variability measures together can enhance information acquired in comparison to when either type of dependent variable is used alone. This analysis revealed statistically reliable main effects of both group, F(1,14) = 14.9, p < .002, and age, F(2,28) = 8.2, p < .002. A statistically reliable Group x Age interaction was also found, F(2,28) = 3.6, p < .04. Post-hoc t tests revealed that the syllable durations of the infants with Down syndrome were equivalently variable to those of the typically developing infants at 2-4 months (infants with Down syndrome, SD = 336 ms, typically developing infants SD = 293 ms, t(7) = .74, p < . 5 , but were more variable at 6-8 months (infants with Down syndrome, SD = 764 ms, typically developing infants, SD = 375 ms, t(7) = 3.2, p < .02, and 10-12 months (infants with Down syndrome, SD = 503 ms, typically developing infants, SD = 296 ms, t(7) = 2.5, p < .04.

In the analysis of variability in utterance durations, a 2 x 3 (Group x Age) ANOVA revealed only a statistically reliable main effect of group, F(1,14) = 6.7, p < .021, indicating that the utterance durations of the infants with Down syndrome, SD = 842 ms, were reliably more variable than those of the typically developing infants, SD = 572 ms. In the analysis of variability in prelinguistic phrase durations, a 2 X 3 (Group x Age) ANOVA revealed only a statistically reliable main effect of group, F(1,14) = 7 . 2 , p < .018, indicating that prelinguistic phrases of the infants with Down syndrome were reliably more variable, SD = 3.4 s , than those of the typically developing infants, SD = 2.5 S.

16 LYNCH ET AL.

1.5

1.2

1.1

Phrase-Final Syllables

0.4 Non-Final 0.3 Syllables

1 I 0.2 L 2-4 ' 6-8 10-12

Age (months)

Fig. 7. Phrase final-syllable lengthening of infants with Down syndrome. Filled circles indicate data for phrase final syllables. Open circles indicate data for all nonfinal syllables within phrases. Durations are expressed in seconds. Error bars = 95% confidence intervals.

Internal Organization and Cohesiveness of Prelinguistic Phrases Similarly to the typically developing infants, the infants with Down syndrome did

not evidence utterance final-syllable lengthening but did evidence phrase final-syllable lengthening. In the analysis of the phrase final lengthening in infants with Down syndrome, statistically reliable main effects of both age, F(2,28) = 9.6, p < .001, and syllable position, F(1,14) = 7.7, p < .015, were found (see Figure 7).

In addition to final lengthening, compression of syllable durations was examined for the infants with Down syndrome. When either syllables or utterances were embedded within phrases, their durations were not globally compressed. In the analysis of syllabic embedding within utterances, the overall pattern of results for the infants with Down syndrome differed slightly from that obtained for the typically developing infants. The infants with Down syndrome did not compress syllable durations in multisyllabic utterances when the utterances were not embedded within prelinguistic phrases, as indicated by a 3 x 2 (Age x Syllable Status) ANOVA in which a statistically reliable main effect of syllable status was not found, F(1,14) = 2.1, p < .173. When utterances were embedded within prelinguistic phrases, statistically reliable main effects of syllable status, F(1,14) = 7.3, p < .017, and age, F(2,28) = 12.5, p < .0001, were found, as well as a Syllable Status x Age interaction, F(2,28) = 3.3, p < .05. Post-hoc analyses indicated that the infants with Down syndrome had monosyllabic utterances that were not longer than the component syllables of multisyllabic utterances at 2-4 months, t(14) = 0.09, p < .931, but were longer at 6-8 months, t(14) = 2.2, p < .049, and at 10-12 months, t(14) = 3.1, p < .008. These data are shown in Figure 8.

The findings of the duration analysis were generally confirmed by an analysis of variability of syllable durations as a function of their embeddedness. The infants' standard deviations in syllable durations were entered into two 3 x 2 x 2 (Age x Syllable Status x Group) ANOVAs. One ANOVA was conducted for syllables not embedded within prelinguistic phrases, and one ANOVA was conducted for syllables embedded


1.5

1.4

1.3

1.2

1.1

1.0

0.9

0.8

0.7 0.6

0.5

0.4

-

- - -

- -

- - - - -

-

Syllables in Monosyllabic Utterances

\ Syllables in 1 Multisyllabic

Utterances I

6-8 10-12 0.3 t o.2 211

Age (months)

Fig. 8. Duration compression in phrased utterances for infants with Down syndrome. Filled circles indicate data for syllables in monosyllabic utterances. Open circles indicate data for component syllables of multisyllabic utterances. Durations are expressed in seconds. Error bars = 95% confidence intervals.

within prelinguistic phrases. The analysis of syllables not embedded within phrases revealed only statistically reliable main effects of group, F(1,28) = 10.5, p < .003, and age, F(2,56) = 11.8, p < .0001. The lack of a reliable main effect of syllable status indicates that variability in durations of syllables in multisyllabic utterances was not reduced in comparison to variability in durations of syllables in monosyllabic utterances.

The analysis of syllables embedded within prelinguistic phrases, however, indicated that variability in durations of syllables in multisyllabic utterances was reduced in comparison to variability in durations of syllables in monosyllabic utterances. This ANOVA revealed statistically reliable main effects of syllable status, F(1,28) = 11.0, p < .002, and age, F(2,56) = 5.8, p < .005, showing that the standard deviations of syllable durations embedded within both prelinguistic phrases and multisyllabic utterances, SD = 329 ms, were statistically less than those of monosyllabic utterances embedded within prelinguistic phrases, SD = 474 ms, for both infant groups, adifference not found between monosyllabic and multisyllabic utterances that were not embedded within prelinguistic phrases.

The final comparison of the infants with Down syndrome with the typically developing infants involved the pattern of cohesion between rhythmic units and corresponding silences as a function of embeddedness. The same pattern of results was obtained for the infants with Down syndrome as for the typically developing infants. Utterance durations were more similar to silences between them and the next nonvegetative vocalization when utterances were embedded within phrases than when they were not, and silences between phrases and the next nonvegetative vocalization were considerably longer than prelinguistic phrases were.

Discussion Prelinguistic vocalizations were composed of a hierarchy of grouping structures

with internal cohesiveness, as reflected by acoustic characteristics and adult perception. The adult judges’ successful identification of prelinguistic phrases was impressive be-

18 LYNCHETAL

t h

(u

v

C .- L

f n

5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1 .o 0.5 0.0

t T

Poetic Line/ Musical Phrase

_ _ _ _ _ _ - _ - -

Metrical Foot Adult Syllable

~ n Syndrome

t

Infants DOW

Phrases RS3 Utterances a Syllables

Fig. 9. Overall rhythmic hierarchies for both typically developing infants and infants with Down syndrome. Duration is expressed in seconds. Error bars = 2 1 standard deviation. Dotted lines indicate optimal durations from some other studies of adult speech, music, and poetry.

cause they were not previously trained in the identification of these structures. The high reliability in location of these phrases suggests that they may have natural perceptual reality for adult caregivers.

In order to illustrate a general proposal about possible universalities in prosodic hierarchies, Figure 9 shows the overall durations of the rhythmic units studied. Three dotted lines extend through the figure to show data obtained by some other investigators. The bottom dotted line indicates the approximate average duration of an adult syllable produced in citation form (e.g., “ba ba ba ba,” about 350 ms, depending on the production context: Smith, 1976); the middle dotted line indicates the average durations of metrical feet in speech (Lehiste, 1973; Nakatani, O’Connor, & Aston, 1981); and the top dotted line indicates a cross-culturally optimal duration of a spoken poetic line (about 3.2 s; Poppel, 1985; Turner, 1985; Wallin, 1901, 191 1). The standard deviations of each of the rhythmic units of the typically developing infants overlapped with the durations of each of the rhythmic units from mature hierarchical systems. In other domains, measures (bars) in music are similar in duration to poetic lines and prelinguistic phrases (Sears, 1902), and attention cycles in infant-caregiver interaction and sucking episodes of newborns occur within 3-6 s (Kaye & Fogel, 1980; Kaye & Wells. 1980). It is also informative to note that an approximately 3-s temporal window is cross- culturally stable across various speech and nonspeech types of intentional, overt human behavior (Schleidt, Eibl-Eibesfeldt, & Poppel, 1987). The 3- to 6-s temporal period has been described as possibly fundamental to human motoric and perceptual function (Fraisse, 1982), and the present findings lend support to this view. The correspondences between infant and adult timing units are pointed out to illustrate the proposal that basic ranges of timing possibilities may be dictated by inherent biological constraints of humans. Perceptual experience, biological maturation, and development of linguistic knowledge may result in adjustment or canalization of rhythmic unit durations (Gottlieb, 1976; Locke, 1993).


Figure 9 also shows that all levels of the rhythmic hierarchy were extended in duration for infants with Down syndrome.The prelinguistic vocal differences found in the present study between the typically developing infants and the infants with Down syndrome were more pronounced and developmentally earlier than in previous compari- sons of other speech characteristics in these groups, suggesting that the current measures could be particularly useful in documentation of precursors to significant speech and language delay later in childhood. Whether the differences between the infant groups are due to motor delay, cognitive delay, or some other factor is not possible to discern at this point because prelinguistic phrasing conceivably draws significant components from each of these domains.

Although infants with Down syndrome had rhythmic units that were longer than those of the typically developing infants, there were no differences between the groups in overall vocal output or in the complexity of the rhythmic units studied. The infant groups produced similar numbers of syllables, utterances, and prelinguistic phrases per minute. The numbers of syllables per utterance and utterances per prelinguistic phrase were also similar between the groups. In addition, the extended durations of rhythmic units in the infants with Down syndrome were accompanied by similar features of phrase internal-cohesive structure as produced by the typically developing infants. Therefore, timing may have been disordered independently of rhythmic complexity and structural cohesiveness in the infants with Down syndrome. The longitudinal patterns, however, of duration compression were different for the infants with Down syndrome in comparison with the typically developing infants. In the analysis of compression of syllable durations, a more pronounced effect was found for both infant groups when utterances were embedded in prelinguistic phrases than when they were not embedded in phrases. The complex motoric delays that are characteristic of children with Down children could have significantly contributed to less stable prelinguistic phrasal structure in these infants as a result of atypical interactions of the speech-motor and respiratory systems. Clarification of this issue should be obtained through detailed studies of speech-motor behavior in infants.

The extended communicative time frames of infants with Down syndrome may account for the vocal clashing phenomenon observed in previous studies of interactions between infants with Down syndrome and their caregivers (e.g., Berger & Cunningham, 1983). Infants with Down syndrome and their caregivers simultaneously vocalize more often than dyads of typically developing infants and their caregivers. Vocal clashing may result from infants with Down syndrome and their parents functioning within different communicative time frames.

Global aspects of social factors might also be related to prelinguistic phrasing. In particular, research has indicated that vocal aspects of caregiver-infant interaction are bidirectional. A number of studies have shown that adults actively modulate their infant- directed communication, such as in speech (e.g., Fernald & Morikawa, 1993; Papousek, Papousek, & Symmes, 1991), singing (Trehub, Unyk, & Trainor, 1993a, 1993b), and sign language (Masataka, 1992). In addition, infants have been shown to “prefer” infant- directed speech over adult-directed speech (Fernald, 1989, as well as approving over disapproving melodic patterns in infant-directed speech (Fernald, 1993; Papousek et al., 1990). It may also be the case that phonetic predictability of nursery rhymes provides a scaffold for language learning (Maclean, Bryant, & Bradley, 1987). The bidirectional character of prelinguistic caregiver-infant vocal transactions has also been indicated by Murray and Trevarthen (1986), who showed that semantic and syntactic characteristics of infant-directed speech of adults was affected by the contingent responding of

20 LYNCH ET AL.

infants. Other recent findings suggest that 3-month-olds’ production of syllabic vocalizations positively influence adult judgments of the infants’ attractiveness as social partners (Bloom, 1990; Bloom, D’Odorico, & Beaumont, 1993). Consideration of the present findings and previous work in the context of the intuitive parenting construct (Papousek & Papousek, 1979, 1982, 1987), which focuses on the adjustments and decisions made within the caregiver-infant dyad without conscious formalization, suggests that prelinguistic phrasing may be an important aspect of the intuitive bond that exists between caregivers and infants because it provides universal communicative frames of infant-caregiver interaction before developmental availability of linguistic communication.

Notes This research was supported in part by Grant #HD28527 from the National Institute of Child Health

& Human Development to M. P. Lynch and by Grants ktDC00484 to D. K. Oller and #DC00935 to R. B. Wilbur from the National Institute of Deafness and Other Communication Disorders. This study benefited from the assistance of Judi Lewis, Devorah Basinger, Sharyse Levine, and Vanessa Lewedag. We thank Dr. Esther Thelen for suggestions about the nonspeech literature and the anonymous reviewers for their insightful comments. The authors are very grateful to the infant subjects and their parents for participating in this longitudinal study. Address correspondence to Michael P. Lynch, Ph.D., Department of Audiology & Speech Sciences, 1353 Heavilon Hall, Purdue University, West Lafayette, IN 47907-1353, U.S.A.

References Aldridge, J. W., Berridge, K. C . , Herman, M., & Zimmer, L. (1993). Neuronal coding of serial order: Syntax

Allen, G . D. (1983). Some suprasegmental contours in French two-year-old children’s speech. Phonerica,

Ardran, G. M., Harker, P., & Kemp, F. H. (1972). Tongue size in Down’s syndrome. Journal ofMenia1 DeJiciency Research, 16, 160-166.

Asgari, M., Pinto, J . P., & Fernald, A. (1993, March). Infants’ sensitivity to musicalphrase structure. Poster presented at the meeting of the Society for Research in Child Development, New Orleans, LA.

Beach, C., Katz, W., Ganguilay, A., Guber, K., McBride, A., & Park, S. (1991, November). Children’s use of prosody to idenfib phrasal units in sentences. Paper presented at the meeting of the Acoustical Society of America, Houston, TX.

Beckman, M . , & Pierrehumbert, J. (1986). Intonational structure in Japanese and English. Phonology Year-

Beek, P. J., & Turvey, M. T. (1992). Temporal patterning in cascade juggling. Journal of Experimental Psychology: Human Perception and Performance, 18, 934-947.

Beek, P. J . , & van Santvoord, A. A. M. (1992). Learning the cascade juggle: A dynamical systems analysis. Journal of Motor Behavior, 24, 85-94.

Berger, J . , & Cunningham, C. C. (1983). Development of early vocal behaviors and interactions in Down’s syndrome and nonhandicapped infant-mother pairs. Developmental Psychology, 19, 322-33 1 .

Blackwell, P. B. (1991). Acoustic and functional characteristics of infants’ disyllables and multisyllabic babbling. Unpublished doctoral dissertation, Purdue University, West Lafayette, IN.

Bloom, K. (1990). Selectivity and early infant vocalization. In J. T. Enns (Ed.), The development ofattention: Research and theory. Amsterdam: Elsevier.

Bloom, K., D’Odorico, L., & Beaumont, S. (1993). Adult preferences for syllabic vocalizations: Generaliza- tions to parity and native language. Infant Behavior and Development, 16, 109-120.

Booi, G. (1983). Principles and parameters in prosodic phonology. Linguistics, 21, 249-280. Bower, G. H. (1970). Organizational factors in memory. Cognitive Psychology, 1 , 18-46. Bower, G . H., & Winzenz, D. (1969). Group strucure, coding, and memory for digit series. Journal of

of grooming in the neostriatum. Psychological Science, 4 , 391-395.

40, 269-292.

book, 3, 255-309.

Experimental Psychology Monographs, 80, (2, Pt. 2), 1-17.

PRELINGUISTIC PHRASING 2 1

Butterworth, G., & Cicchetti, D. (1978). Visual calibration of posture in normal and motor retarded Down’s

Cardoso-Martins, C., Mervis, C. B., & Mervis, C. A. (1985). Early vocabulary acquisition by children with

Chomsky, N., & Halle, M. (1968). The sound pattern of English. New York: Harper & Row. Cooper, W. E., & Paccia-Cooper, J. (1980). Syntax and speech. Cambridge, MA: Harvard University Press. Cruttenden, A. (1986). Intonation. New York: Cambridge University Press. Crystal, D. (1969). Prosodic systems andintonation in English. Cambridge, MA: Cambridge University Press, Cynx, J. (1990). Experimental determination of a unit of song production in the zebra finch (Taeniopygiu

guttata). Journal of Comparative Psychology, 104, 3- 10. Darwin, C. J. (1975). On the dynamic use of prosody in speech perception. In A. Cohen & S . G. Nooteboom

(Eds.), Structure and process in speech perception (pp. 178-194). New York Springer-Verlag. de Boysson-Bardies, B., Sagart, L., & Durand, C. (1984). Discernible differences in the babbling of infants

according to target language. Journal of Child Language, 11 , 1-15. Dowling, W. J. (1973). Rhythmic groups and subjective chunks in memory for melodies. Perception and

Psychophysics, 14, 37-40. Eilers, R. E., Widen, J. E. , Urbano, R., Hudson, T., & Gonzales, L. (1991). Optimizations of automated

hearing test algorithms: A comparison of data from simulations and young children. Ear and Hewing,

Epstein, S . (1980). The stability of behavior: 11. Implications for psychological research. American Psycholo-

Evans, J. R., & Clynes, M. (1986). Rhythm in psychologicul und musicalprocesses. Springfield, IL: Thomas. Farkas, L. G., Munro, I. R., & Kolar, J. C. (1985). Abnormal measurements and disproportions in the face

of Down’s syndrome patients: Preliminary report of an anthropometric study. Plastic and Reconstructivr Surgery, 75, 159-167.

Fentress, J. C. (1989). Developmental roots of behavioral order: Systematic approaches to the examination of core developmental issues. In M. R. Gunnar & E. Thelen (Eds.), Systems and development: The Minnesotu symposium on child psychology (Vol. 22) (pp. 35-75). Hillsdale, NJ: Erlbaum.

Fentress, J. C., & Stillwell, F. P. (1973). Grammarofamovement sequence in inbred mice. Nature, 244,52-53. Fernald, A. (1985). Four-month-old infants prefer to listen to motherese. Infant Behavior and Development,

Fernald, A. (1993). Approval and disapproval: Infant responsiveness to vocal affect in familiar and unfamiliar languages. Child Development, 64, 657-674.

Fernald, A., & Kuhl, P. (1987). Acoustic determinants of infant preference for motherese speech. Infant Behavior and Development, 10, 279-293.

Fernald, A,, & McRoberts, G . (in press). Prosodic bootstrapping: A critical analysis of the argument and the evidence. In J. L. Morgan & K. Demuth (Eds.), Signal to syntax: Bootstrapping from speech to syntax in early acquisition. Hillsdale, NJ: Erlbaum.

Fernald, A., & Morikawa, H. (1993). Common themes and cultural variations in Japanese and American mothers’ speech to infants. Child Development, 64, 637-656.

Fink, G . B., Madaus, W. K., & Walker, G. F. (1975). A quantitative study of the face in Down’s syndrome. American Journal of Orthodontics, 69, 540-553.

Fonagy, I., & Magdics, K. (1960). Speed of utterance in phrases of different lengths. Language and Speech,

Fraisse, P. (1982). Rhythm and tempo. In D. Deutsch (Ed.), The psychology of music (pp. 203-254). New

Frostad, W. A,, Cleall, J. F., & Melosky, L. C. (1971). Craniofacial complex in the Trisomy 21 syndrome

Gee, J. P., & Grosjean, F. (1983). Performance structures: A psycholinguistic and linguistic appraisal.

Gentner, D. R. (1987). Timing of skilled motor performance: Tests of the proportional duration model.

Gerken, L., Jusczyk, P. W., & Mandel, D. R. (1994). When prosody fails to cue syntactic structure: 9-

Gottlieb, G. (1976). Conceptions of prenatal development: Behavioral embryology. Psychological Review,

Grosjean, F., & Lane, H. (1981). Temporal variables in the perception and production of spoken and sign languages. In P. D. Eimas & J. L. Miller (Eds.), Perspectives on the study of speech (pp. 207-237). Hillsdale, NJ: Erlbaum.

syndrome infants. Perception, 7, 513-525.

Down syndrome. American Journal of Mentul Dejciency, 90, 177-184.

12, 199-204.

gist, 35, 790-806.

8, 181-195.

3, 179-192.

York: Academic Press.

(Down’s syndrome). Archives of Oral Biology, 16, 707-722.

Cognitive Psychology, 15, 41 1-458.

Psychological Review, 94, 255-276.

months-olds’ sensitivity to phonological versus syntactic phrases. Cognition, 51, 237-265.

83, 215-234.

22 LYNCH ET AL.

Halliday, M. (1967). Intonation and grammar in British English. The Hague: Mouton. Hauser, M. D., & Fowler, C . A. (1992). Fundamental frequency declination is not unique to human speech:

Evidence from nonhuman primates. Journal of the Acousticd Society of America, 91 363-369. Hirsh-Pasck, K., Kemler Nelson, D. G., Jusczyk, P. W., Wright-Cassidy, K., Druss, B. , & Kennedy, L.

(1987). Clauses are perceptual units for young infants. Cognition, 26, 269-286. Jusczyk, P. W., Hirsh-Pasek, K., Kemler Nelson, D. G. , Kennedy, L., Woodward, A,, & Piwoz. J . (1992).

Perception of acoustic correlates of major phrasal units by young infants. Cognitive Psychology 24, 252-293.

Jusczyk, P. W., & Krumhansl, C . L . (in press). Pitch and rhythmic patterns affecting infants’ sensitivity to musical phrase structure. Journal of Expeimental Psychology: Human Perception and Performance.

Kaye, K., & Fogel, A. (1980). The temporal structure of face-to-face communication between mothers and infants. Developmental Psychology, 16, 454-464.

Kaye. K., & Wells, A. J. (1980). Mothers’ jiggling and the burst-pause pattern in neonatal feeding. Inf i tnt Behavior and Development, 3 , 29-46.

Kemler Nelson, D. G . , Hirsh-Pasek, K., Jusczyk, P. W., & Wright-Cassidy, K. (1989). How the prosodic cues in motherese might assist language learning. Journal of Child Language, 16, 53-68.

Kent, R. D., Mitchell, P. R., & Sancier, M. (1991). Evidence and role of rhythmic organization in early vocal development in human infants. In J. Fagard & P. H. Wolff (Eds.), The development qft iming c.ontro1 and temporal orgcznizution in coordinated action (pp. 135-149). Elsevier Science Publishers.

Klatt, D. H. (1975). Vowel lengthening is syntactically determined in a connected discourse. Journal qf Phonetics, 3 , 129-140.

Kohler, K. J. (1983). Prosodic boundary signals in German. Phoneticu, 40, 89-134. Konopczynski, G. (1986). Vers un modele developpemental du rythme Francais: Problemes d’isochronie

reconsideres a la lumiere des donnees de l’acquisition du language. Bulletin de l‘lnsritut de Pkonetiyue de Grenoble, 15, 157-190.

Krumhansl, C. L., & Jusczyk, P. W. (1990). Infants’ perception of phrase structure in music. P.sychological Science, 1 , 70-73.

Ladd. D. R. (1986). Intonational phrasing: The case for recursive prosodic structure. Phonology Yearbook. 3, 31 1-340.

Ladd, D. R., & Campbell, N. (1991). Theories of prosodic slructure: Evidence from syllable duration. Proceedings of the XI1 International Congress of Phonetic Sciences. Aix-en-Provence, France.

Lehiste, I . (1973). Rhythmic units and syntactic units in production and perception. Journal of the Acoustical Society of America, 54, 1228-1234.

Lerdahl, F., & Jackendoff, R. (1983). A generutive zheory oftonal music. Cambridge, MA: MIT Press. Levitt, A. G., & Utman, J. G . A. (1992). From babbling towards the sound systems of English and French:

a longitudinal two-case study. Journal of Child Language. 19, 19-49. Levitt, A. G., & Wang, Q. (1991). Evidence for language-specific rhythmic influences in the reduplicative

babbling of French- and English-learning infants. Language and Speech. 34, 235-249. Liberman, M., & Prince, A. (1977). On stress and linguistic rhythm. Linguistic Inquiry, 8, 249-336. Lieberman, P. (1967). Intonation. perception, and language. Cambridge, MA: MIT Press. Lindblom, B. (1978). Final lengthening in speech and music. In E. Garding, G. Bruce, & R. Bannert (Eds.),

Lindblom, B., & Rapp, K. (1973). Some temporal regularities of spoken Swedish. PILUS (Pupersfrom tho

Locke. J . L. (1993). The child’s path to spoken language. Cambridge: MA: Harvard University Press. Lockman, J . J., & Thelen, E. (1993). Developmental biodynamics: Brain, body, behavior connections. Child

Lyberg, B. (1977). Some observations on the timing of Swedish utterances. Journal ofPhonetics, 5, 49-59. Lynch. M. P., & Eilers, R. E. (1991). Pespectives on early language from typical development and Down

syndrome. In N. W. Bray (Ed.), International review of research in mental retardation (Vol. 17, pp. 55-90). New York: Academic Press.

Lynch, M. P., Oller, D. K., & Steffens, M. L. (1989). Development of speech-like vocalizations in a child with congenital absence of cochleas: The case of total deafness. AppliedPsycho/inguj.rrics, 10, 315-333.

Lynch. M. P., Oller, I>. K., Steffens, M. L., Levine, S. L., Basinger, D., & Umbel, V. (in press). The onset of speech-like vocalizations in infants with Down syndrome. American Journal on Mprrtal Rctardtrtion.

Maclean. M., Bryant P., & Bradley, L . (1987). Rhymes, nursery rhymes, and reading in early childhood. Merrill Palmer Quarterly, 33, 255-281.

MacNeilage, P. F., & Davis, B. (1990). Acquisition of speech production: Frames, then content. In M.

Nordic, prosody (pp. 85-101). Lund University: Department of Linguistics.

fnstitute of Linguistics, University uf StockhotmJ, No. 21.

Development, 64. 953-959.


Jeannerod (Ed.), Attention and performance. XIII: Motor representation and control (pp. 453-476). Hillsdale, NJ: Erlbaum.

Malecot, A,, Johnston, R. , & Kizziar, P. A. (1972). Syllabic rate and utterance length in French. Phoentic,a, 26, 235-251.

Marler, P., & Sherman, V . (1983). Song structure without auditory feedback: Emendations of the auditory template hypothesis. Journal of Neuroscience, 3, 5 17-531.

Marler, P., & Sherman, V. (1985). Innate differences in singing behavior of sparrows reared in isolation from adult conspecific song. Animal Behauior, 33, 57-71.

Martin, J. G. (1972). Rhythmic (hierarchical) versus serial structure in speech and other behavior. Psychohgi- cal Reuiew, 79, 487-509.

Martin, J. G. (1975). Rhythmic expectancy in continuous speech perception. In A. Cohen & S. G. Nooteboom (Eds.), Structure and process in speech perception (pp. 161-177). New York: Springer-Verlag.

Masataka, N. (1992). Motherese in a signed language. Infant Behavior and Development, 15, 453-460. Miller, J. F. (1988). The developmental asynchrony of language development in children with Down syndrome.

In L. Nadel (Ed.), The psychobiology qfDown syndrome (pp. 167-198). Cambridge, MA: MIT Press. Morgan, J. L. (1986). From simple input to complex grammar. Cambridge, MA: MIT Press. Murray, L., & Trevarthen, C. (1986). The infant’s role in mother-infant communication. Journal of Child

Nadel, L. (1988). The psychobiology of Down syndrome. Cambridge, MA: MIT Press. Nakatani, L. H., O’Connor, K. D., & Aston, C. H. (1981). Prosodic aspects of American English speech

Nespor, M., & Vogel, I. (1983). Prosodic structure above the word. In A. Cutler & D. R. Ladd (Eds.),

Nespor, M., & Vogel, 1. (1986). Prosodic phonology. Dordrecht, Holland: Foris. Nooteboom, S. G., & Cohen, A. (1975). Anticipation in speech production and its implications for perceptions.

In A. Cohen & S. G. Nooteboom (Eds.), Structure and process in speech perception (pp. 124-145). New York: Springer-Verlag.

Oller, D. K. (1973). The effect of position in utterance on speech segment duration in English. Journal of the Acoustical Society of America, 54, 1235-1247.

Oller, D. K. (1986). Metaphonology and infant vocalizations. In B. Lindblom & R. Zetterstrom (Eds.), Precursors of early speech (pp. 21-36). Basingstroke, Hampshire, United Kingdom: Macmillan.

Oller, D. K. & Eilers, R. E. (1988). The role of audition in infant babbling. Child Development, 59, 441-449. Oller, D. K., Eilers, R. E., Bull, D. H., & Carney, A. E. (1985). Prespeech vocalizations of a deaf infant:

A comparison with normal metaphonological development. Journal of Speech and Hearing Research, 28, 47-63.

Oller, D. K., & Lynch, M. P. (1992). Infant vocalizations and innovations in infraphonology: Toward a broader theory of vocal development and disorders. In C. A. Ferguson, L. Menn, & C. Stoel-Gammon (Eds.), Phonological deuelopment (pp. 509-536). Parkton, MD: York Press.

Oller, D. K., & Smith, B. L. (1977). Effect of final-syllable position on vowel duration in infant babbling. Journal of the Acoustical Society of America, 62, 994-997.

Ozdamar, O., Eilers, R. E., Miskiel, E., & Widen, J. (1990). Classification of audiograms by sequential testingusing adynamic Bayesianprocedure. Journal of the Acoustical Society ofAmerica, 88,2171-2179.

Palmer, C., & Kelley, M. H. (1992). Linguistic prosody and musical meter in song. Journal uf Memory and Language, 31, 525-542.

Papousek, H., & Papousek, M. (1979). The infant’s fundamental adaptive response system in social interaction. In E. Thoman (Ed.), Origins of the infant’s social responsiveness (pp. 175-208). Hillsdale, NJ: Erlbaum.

Papousek, H., & Papousek, M. (1982). Infant-adult social interactions: Theirorigins, dimensions, and failures. In T. M. Field, A. Huston, H. C. Quay, L. Troll, & G. E. Finley (Eds.), Reuiew of human development (pp. 148-163). New York: Wiley.

Papousek, H., & Papousek, M. (1987). Intuitive parenting: A dialectic counterpart to the infant’s precocity in integrative capacities. In J . D. Osofsky (Ed.), Handhookofinfant deuelopmrnt (2nd ed.) (pp. 669-720). New York: Wiley.

papousek, M., Papousek, H., & Symmes, D. (1991). The meanings of melodies in motherese in tone and stress languages. Infant Behavior and Deuelopment, 14, 415-440.

Papousek, M., Bornstein, M. H., Nuzzo, C., Papousek, H., & Symmes, D. (1990). Infant responses to prototypical melodic contours in parental speech. Infant Behavior and Deuelopment, 13, 539-545.

Papousek, M., Papousek, H., & Bornstein, M. H. (1985). The naturalistic vocal environment of young infants:

Language, 13, 15-29.

rhythm. Phonetica, 38, 84-106.

Prosody: Models and measurements. New York: Springer-Verlag.

’

24 LYNCH ET AL.

On the significance of homogeneity and variability in parental speech. In T. Field & N . Fox (Eds.), Social perception in infants (pp. 269-297). Norwood, NJ: Ablex.

Payne, K., Tyack, P., & Payne, R. (1984). Progressive changes in the songs of humpback whales (Metaptera novaeangeliae): A detailed analysis of two seasons in Hawaii. In R. Payne (Ed.), Communication and behavior of whales (pp. 9-57). Boulder, CO: Westview Press.

Pike, K. L . (1945). The intonation of American English. Ann Arbor: University of Michigan Press. Poppel, E. (1985). Mindworks: Time and conscious experience. Boston: Harcourt Brace Jovanovich. Price, P. J . , Ostendorf, M., Shattuck-Hufnagel, S. , & Fong, C. (1991). The use of prosody in syntactic

Robb, M. P., & Saxman, J. H. (1990). Syllable durations of preword and early word vocalizations. Journal

Rock, I., & Palmer, S. (1990). The legacy of Gestalt psychology. Scient$c American, 263(6), 84-90. Schleidt, M., Eibl-Eibesfeldt, I., & Poppel, E . (1987). A universal constant in temporal segmentation of

Scott, D. R. (1982). Duration as a cue to the perception of a phrase boundary. Journal of the Acoustical

Sears, G. H. (1902). A contribution to the psychology of rhythm. American Journal ofpsychology, 13 ,2841 , Selkirk, E . (1980). The role of prosodic categories in English word stress. Linguistic Inquiry, 11, 563-605. Selkirk, E. (1984). Phonology and syntax: The relation between sound and structure. Cambridge, MA:

Shaffer, L . H. (1982). Rhythm and timing in skill. Psychological Review, 89, 109-122. Shaffer, L . H., Clarke, E. F . , &Todd, N. P. (1985). Meter and rhythm in piano playing. Cognition, 20,61-77. Smith, B. L. (1976). Development of some temporal parameters of English speech production. Unpublished

doctoral dissertation, University of Texas. Smith, B. L. (1992). Relationships between duration and temporal variability in children’s speech. Journal

of the Acoustical Society of America, 91, 2165-2174. Smith, B. L. (in press). Effects of experimental manipulations and intrinsic contrasts on relationships between

duration and temporal variability in children’s and adults’ speech. Journal of Phonetics. Smith, L., & von Tetzchner, S. (1986). Communicative, sensorimotor, and language skills of young children

with Down syndrome. American Journal of Mental Dejiciency, 91, 57-66. Snow, D. (1992, May). Final-syllable lengthening and intonation in early child speech. Paper presented at

the 13th Child Phonology Conference, University of Illinois, Urbana. Stark, R. E. (1980). Stages of speech development in the first year of life. In G. Yeni-Komshian, J . Kavanagh,

& C. Ferguson (Eds.), Child phonology, Vol. I : Production (pp. 73-90). New York: Academic Press. Strangert, E. (1978). Temporal aspects of rhythm in Swedish. In E. Garding, G. Bruce, & R. Bannert (Eds.),

Nordic prosody (pp. 103-108). Lund University: Department of Linguistics. Sturges, P. T., & Martin, J . G. (1974). Rhythmic structure in auditory temporal pattern perception and

immediate memory. Journal of Experimental Psychology, 102, 377-383. Thelen, E . (1991). Motor aspects of emergent speech: A dynamic approach. In N. Krasnegor (Ed.), Biohehuv-

ioral foundations of language (pp. 339-362). Hillsdale, NJ: Erlbaum. Thompson, P. O., Findley, L. T., & Vidal, 0. (1992). 20-Hz pulses and other vocalizations of fin whales,

Balaenoptera physalus, in the Gulf of California, Mexico. Journal of the Acoustical Society of America,

Trehub, S. E., Unyk, A. M., & Trainor, L. J . (1993a). Adults identify infant-directed music across cultures.

Trehub, S. E., Unyk, A. M., & Trainor, L. J. (1993b). Maternal singing in cross-cultural perspective. lnfanr

Turner, F. (1985). Natural classicism: Essays on literature and science. New York: Paragon House, Turvey, M. T., & Fitzpatrick, P. (1993). Commentary: Development of perception-action systems and

general principles of pattern formation. Child Development, 64, 1175-1 190. Tyack, P. (1986). Population biology, social behavior, and communication in whales and dolphins. Trends

in Ecology and Evolution (TREE), I , 144-150. Van Borsel, J . (1988). An analysis ofthe speech of five Down’s syndrome adolescents. Journal of Communica-

tion Disorders, 21, 409-421. Wachs, T. D. (1991). Conceptualization and measurement of organism-environment interactions: Synthesis

and conclusions. In T. D. Wachs & R. Plomin (Eds.), Conceptualization and measurement oforganism- environment interaction (pp. 162-182). Washington, DC: American Psychological Association.

Wahrman, J., & Fried, K. (1970). The Jerusalem prospective newborn survey of Mongolism. Annuls qf’the New York Academy of Science, 171, 341-360.

disambiguation. Journal of the Acoustical Society of America, 90, 2956-2970.

of Speech and Hearing Research. 33, 583-593.

human short-term behavior. Nuticrwissenschaften, 74, 289-290.

Society of America, 71, 996-1007.

MIT Press.

92, 3051-3057.

Infant Behavior and Development, 16, 193-21 1.

Behavior and Development, 16, 285-295.


Wallin, J . E. W. (1901). Researches on the rhythmof speech. Studies From the Yale Psychological Laboratory,

Wallin, J. E. W. (1911). Experimental studies of rhythm and time. Psychological Review, 18, 100-131. Wightman, C. W., Shattuck-Hufbnagel, S., Ostendorf, M., & Price, P. (1992). Segmental durations in the

vicinity of prosodic phrase boundaries. Journal of the Acoustical Society of America, 91, 1707-1717. Wilbur, R. B. (1993). Syllables and segments: Hold the movement and move the holds! In G . R. Coulter

(Ed.), Phonetics andphonology. Vol. 3: Current issues in ASL phonology. New York: Academic Press. Wilbur, R. B., & Nolen, S. B. (1986). The duration of syllables in American Sign Language. Language and

Speech, 29, 263-280. Wingfield, A. (1975). The intonation-syntax interaction: Prosodic features in perceptual processing of sen-

tences. In A. Cohen & S. G. Nooteboom (Eds.), Structure and process in speech perception (pp. 146-160). New York: Springer-Verlag.

Zlatin-Laufer, M. (1980). Temporal regularity in prespeech. In T. Murray & A. Murray (Eds.), Infant communication: Cry and early speech (pp. 284-309). Houston: College-Hill.

9, 1-142.

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