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C Stoel-Gammon

Publications and source records attributed to C Stoel-Gammon.

15 recordsLinked to original sources
PubMed1997

Truncation patterns in English-speaking children's word productions.

This study examines English-speaking children's truncation patterns (i.e., syllable deletion patterns) in multisyllabic words to determine if they are consistent with metrical constraints or perceptual biases. It also examines segmental influences on children's truncations. Children, age 22-34 months, produced three-syllable novel and real words and four-syllable real words, which varied across stress and segmental pattern. Results revealed a significant stress pattern effect on truncation rate, but findings were not consistent with metrical or perceptual salience predictions. The clearest account of the findings came from an analysis of truncation rate across individual words: Children truncated WSW (weak-strong-weak) words and words that contained intervocalic sonorants more frequently than other words. Analysis of truncation patterns in SWW and SWSW words revealed that final unstressed syllables were more frequently preserved than nonfinal unstressed syllables. Findings support the interaction between metrical, syllabic, and acoustic salience factors in children's multisyllabic word productions.

Child Language↗
PubMed1996

Consonant-vowel interdependencies in babbling and early words: preliminary examination of a locus equation approach.

Consonant-vowel productions at two distinct stages of language development were studied in a single female child. At 12 months canonical babbling syllables (N = 144) identified by a panel of listeners as comprising [bV], [dV], and [gv] tokens were acoustically analyzed by measuring F2 transition onset and F2 midvowel frequencies and plotting their relationship as locus equations for each stop category. A regression analysis performed on these scatterplots revealed differential slopes and y-intercepts as a function of stop place. The same analysis was performed 9 months later on CV utterances (N = 243) produced as syllable-initial segments of real words by the same child. Whereas labial and velar locus equation parameters moved toward more adult-like values, alveolar slope and y-intercept moved away from adult values and more in the direction of decreased coarticulation between vowel and consonant. There was greater scatter of data points around the regression line for production of words compared to babbling. These results are compared to locus equations obtained from 3-5-year-olds and adults. Locus equations appear to be useful as an empirical developmental probe to document how CV productions gradually approach adult categorical standards.

Cross-Sectional Studies↗
PubMed1995

Acoustic correlates of stress in young children's speech.

This study examined the acoustic correlates of stress in children's productions of familiar words. Previous research has employed experimental words rather than familiar words to examine children's phonetic marking of stress, or has not adequately controlled for phonetic environment. Subjects in this study included 22 children, aged 18-30 months, and 6 adults. Fundamental frequency, duration, and amplitude measures were extracted from stressed and unstressed syllables in two types of comparisons: one that controlled phonetic environment and syllable position (interword) and one that measured the relative effects of stress within the same word (intraword). When the tokens were analyzed on the basis of target stress pattern, results revealed no differences between adults and children in their acoustic marking of stress. Listener judgments showed that approximately 30% of children's two-syllable productions were coded unreliably or were perceived as inaccurately stressed. Overall findings indicate that children control fundamental frequency, amplitude, and duration to derive perceptually identifiable stress contrasts in the majority of their productions but they are not completely adult-like in their marking of stress.

Adult↗
PubMed1994

Cross-language differences in phonological acquisition: Swedish and American /t/.

Our understanding of phonological acquisition has benefited immensely from cross-linguistic investigations which allow researchers to separate biological and learned factors. To date, most cross-linguistic studies have focused either on differences in phonetic inventories or on differences in frequency of occurrence of particular phonetic and phonological properties in the adult language. This paper describes a third type of study: comparisons of segments that occur in two (or more) languages but differ in their phonetic properties. We present perceptual and acoustic analyses of adult and child productions of word-initial alveolar /t/ in American English and dental /t/ in Swedish. Results showed that listeners' perception of place of articulation was strongly associated with language (alveolar: American English, dental: Swedish) for both adult and child tokens, and was effective in assigning individual speakers to language groups. Three acoustic measures, voice onset time, burst intensity and burst spectral diffuseness correlated with language for both child and adult tokens; the latter two measures correlated with perception as well. The findings suggest that American and Swedish children at 30 months of age have acquired some language-specific phonetic aspects of /t/ phonemes.

Cross-Cultural Comparison↗
PubMed1994

Measuring phonology in babble and speech.

Procedures for measuring prelinguistic vocalizations and early phonological development are described and illustrated. The prelinguistic measures indicate that production of supraglottal consonants in consonant-vowel syllables is correlated with subsequent speech and language development and that limited use of consonants can serve as a way to identify children who are at risk for speech and language disorders. Three measures of meaningful speech are discussed, two based on accuracy of production, one on error patterns. All three correlate with severity of involvement, but as yet their relationship to speech intelligibility is unclear.

Articulation Disorders↗
PubMed1994

Nonlinear phonology: introduction and clinical application.

The purpose of this tutorial is to introduce a recent advance in phonological theory, "nonlinear phonology," which differs fundamentally from previous theories by focusing on the hierarchical nature of relationships among phonological units. We first introduce the basic concepts and assumptions of nonlinear phonological theory and then demonstrate clinical applications of the theory for assessment and intervention. Data from a child with a severe phonological disorder are used to illustrate aspects of nonlinear theory. The data are first analyzed in terms of phonological processes in order to provide the readers with a familiar starting point for comprehension and comparison. The nonlinear frameworks are shown to provide a deeper analysis of the child's phonological system than the phonological process analyses and to lead to a more clearly defined intervention plan.

Articulation Disorders↗
PubMed1992

The acquisition of unrounded vowels in English.

This study investigated developmental patterns of acquisition of the unrounded American English vowels /i, I, e, e, ae, a/ by following 6 normally developing children from 22 to 30 months of age. The subjects were examined at approximately 22, 26, and 30 months of age. Results showed that, in general, /i/ and /a/ were mastered early and /I/ and /e/ were least accurate throughout the period of the study. Upon inspection of errors, the following three classes of production errors were identified: (a) intertrial production variability, (b) context-sensitive substitutions, and (c) context-free systematic substitution patterns, or articulatory processes. A decrease in production variability and in the occurrence of articulatory processes with age generally coincided with a gradual improvement in accuracy of production. However, substitutions of lower vowels for /I/ were persistent, and the pattern was observed even at 30 months of age. Individual variation was also evident in the production accuracy, the substitution patterns, and the manner of articulatory improvement.

Articulation Disorders↗
PubMed1991

Assessing phonology in young children.

We have presented a discussion of three important concepts regarding early phonological assessment. The first is that the child's language level must be considered in collecting and analyzing a sample and in interpreting the results. For a child with age-level language abilities, the sample should consist of both a single-word test and a running speech sample; both independent and relational analyses are appropriate. For a child with delayed expressive language and a small productive vocabulary, a sample comprised of spontaneous productions is more appropriate. In this case, the sample should be analyzed in terms of sound classes and syllable and word shapes that occur; a phonological process analysis is inappropriate. Lexical selection patterns should be noted. The results of the analyses should be interpreted in view of the expectations for the child's language level. A child with a normally developing language system is expected to have more advanced phonology than a child of the same age with delayed language. Thus, a child with a large vocabulary and word combinations is expected to have an expanding phonological system, with a full range of sound classes and syllable and word shapes. If a child is delayed in language and is still within the first 50-word stage, the expectation is that the phonological system will be more limited. Critical features for the phonology of early productive vocabulary have been identified. Lack of one or more of these features is indicative of atypical phonological development at any age and language level. The second concept is that the phonological system as a whole must be considered. In particular, the analyses and expectations should be based on the presence or absence of sound classes and syllable shapes rather than on sounds per se. Lack of an entire class or syllable structure would be cause for concern; lack of a particular sound, even though it has been shown to be acquired early, would not be. Thus, lack of the entire fricative class at 36 months would be of concern, whereas errors on /f/, which according to Prather et al., 1975, is mastered by this age, would not be. The third important concept emerges from the case studies; both studies demonstrate that longitudinal assessment is necessary to document changing profiles over the course of development. A child such as David, who has a normal-but-delayed profile in language and phonology at one age, may subsequently exhibit atypical patterns as phonology and language dissociate.(ABSTRACT TRUNCATED AT 400 WORDS)

Articulation Disorders↗
PubMed1990

Down syndrome. Effects on language development.

The newly formed picture that emerges from these recent investigations of language in children with Down syndrome must include the following: (a) language production among children with Down syndrome lags behind expected performance based on mental age; (b) in many children with Down syndrome language production skills are not commensurate with comprehension skills; the number of subjects who exhibit this uneven profile increases with age; (c) lexical and syntactic development are asynchronous in Down syndrome with syntax lagging behind; and (d) syntactic development, as measured by MLU, is characterized by periods of relatively rapid linear growth alternating with extended plateaus. Although answering some questions, these findings raise new issues that must be addressed. However, it seems clear that the traditional "slow-but-normal" characterization of the language of children with Down syndrome is no longer tenable. Instead, we must begin to think in terms of specific properties that are unique to the development of language by children with Down syndrome.

Adolescent↗
PubMed1988

Prelinguistic vocalizations of hearing-impaired and normally hearing subjects: a comparison of consonantal inventories.

Phonetic transcriptions of 48 babbling samples from 11 normally hearing subjects, aged 4-18 months, and 39 samples from 14 hearing-impaired (HI) subjects, aged 4-39 months, were analyzed to determine the inventory of consonantal phones for each recording session. Group comparisons revealed that inventories of the hearing-impaired subjects were generally smaller than those of the hearing infants and that they evidenced little change in size prior to 20 months. Analysis of place and manner of articulation of supraglottal phones in the inventories showed that, compared with inventories of the normally hearing subjects, inventories of HI subjects with sensori-neural loss tended to have (a) a higher proportion of labial consonants; (b) a higher proportion of prolongable consonants such as nasals, glides and fricatives, and syllabic consonants; (c) a lower proportion of alveolars; and (d) a lower proportion of stops and nonsyllabic affricates. Differences were also observed between the inventories of hearing-impaired subjects with sensori-neural loss and those with conductive loss and between younger and older hearing-impaired subjects. These findings suggest that hearing loss affects the nature of the consonantal repertoire in the prespeech vocalizations of hearing-impaired subjects.

Articulation Disorders↗
PubMed1986

Babbling development of hearing-impaired and normally hearing subjects.

Phonetic transcriptions of babbling samples from 11 normally hearing subjects, age 4-18 months, were compared with samples from 11 hearing-impaired subjects, age 4-28 months. Longitudinal data were available for all hearing babies and for 8 of the 11 hearing-impaired subjects. The analysis focused on two measures: (a) size of consonantal repertoire over time and (b) proportional occurrence of multisyllabic consonant-vowel utterances. On average, the normally hearing subjects evidenced an increase in size of their consonantal repertoires with age; in contrast, the hearing-impaired subjects in the same age range had smaller repertoires that decreased over time. Comparison of multisyllabic utterances revealed a general tendency for the hearing-impaired subjects to produce fewer multisyllabic utterances containing true consonants and for some of the hearing-impaired children to produce a high proportion of vocalizations with glides or glottal stops. These findings suggest both qualitative and quantitative differences in the babbling of the two groups.

Female↗
PubMed1985

Phonetic inventories, 15-24 months: a longitudinal study.

Longitudinal samples of meaningful speech of 34 normally developing children were analyzed to determine the range and types of consonantal phones produced at 15, 18, 21, and 24 months. Separate inventories for word-initial and word-final consonants were constructed for each child at each age level. Group analyses showed that early inventories in initial position were composed primarily of voiced anterior stops, nasals, and glides; by 24 months, voiceless stops, velars, and a few fricatives were also included. In final position, inventories consisted primarily of voiceless stops and alveolar consonants. There was a strong tendency for the voiced stops to appear first in initial position and for [t] and [r] to appear first in word-final. Individual analyses of place and manner of articulation revealed highly similar patterns across subjects. The findings are related to other longitudinal research in early phonological development and to studies of babbling of younger subjects and correct productions of older subjects.

Child Language↗
PubMed1983

A longitudinal study of the development of stop consonant production in normal and Down's syndrome children.

In order to compare phonological development in normal and Down's syndrome children, longitudinal observations were made of four normal children from 18 to 36 months of age and five Down's syndrome children from 3 to 6 years of age. Singleton stops and stop clusters were analyzed to determine if the Down's syndrome children evidenced phonological processes and other sound patterns similar to those of the normal children. Although quite similar patterns were observed for the two groups, the Down's syndrome children showed considerable delay in comparison to the normally developing children.

Child↗