Revisiting frequencies of phonological sound classes in speech input: Change over time in child-directed speech.

The purpose of the current study was to revisit a controversial topic: whether frequencies of phonological consonant and vowel classes differ in speech directed to children and to adults. In addition, the current study investigated whether the frequency of phonological consonant and vowel classes changes with children's increasing chronological and/or developmental age. This study analyzed speech input from 44 adults to four different age groups of listeners (i.e., three groups of children at 6, 18, and 36 months of age and one group of adult listeners) in terms of frequency of occurrence of consonant and vowel classes. Results revealed that consonant stop, nasal, fricative and glide manner classes as well as all four consonant place classes were significantly different in speech directed to the four different age groups. A perspective is discussed to better understand the nature of frequency input of phonological sound classes.

Bye-Bye Bunny: Place and Manner Sequences in Children's C1VC2V-Shaped Words.

PURPOSE: Place and manner of articulation in American English-learning children's salient consonant-vowel-consonant-vowel (C1VC2V) target words (e.g., baby, bunny, and cookie) were compared with their actual productions of these words. We hypothesized that target words with repeated place and/or manner characteristics in C1VC2V consonant sequences would be matched in children's actual productions more frequently than target words with variegated place and manner sequences. This hypothesis was based on a proposal that children use available production system capacities to produce salient word forms derived from perceptual input on those word forms. METHOD: Place and manner sequences were analyzed in 2,092 tokens of C1VC2V target words produced by 18 typically developing children in the single-word period. All data were from these children's spontaneous functional speech in a familiar speaking context. Both target word forms and actual child productions of those targets were analyzed. RESULTS: Results indicated that C1VC2V word target sequences predominantly consisted of repetitions in both place and manner of articulation (e.g., labial-labial, stop-stop). Targets with repetitions of consonant sequences were matched more frequently than targets with variegated sequences for both place and manner (e.g., labial-coronal, stop-nasal) in these children's actual productions. Results also indicated that C1VC2V target words beginning with a labial consonant (e.g., baby, bunny, and piggy) were matched in children's actual productions more frequently than words with coronal or dorsal consonant onsets (e.g., daddy and cookie). DISCUSSION: In C1VC2V word forms, occurring in early output, children's actual productions matched their target word sequences when the words consisted of repeated sequences in both place and manner. These results suggest that salient target words with repeated sequences may help children support increases in their repertoire of meaningful vocalizations during the transition from babbling to meaningful speech.

Relationship between the target word form and children's productions: place of articulation in Consonant-Vowel-Consonant (C1VC2) words in American English.

The aim of the present study was to investigate relationships between characteristics of children's target words and their actual productions during the single-word period in American English. Word productions in spontaneous and functional speech from 18 children acquiring American English were analyzed. Consonant sequences in 3,328 consonant-vowel-consonant (C1VC2) target words were analyzed in terms of global place of articulation (labials, coronals, and dorsals). Children's actual productions of place sequences were compared between target words containing repeated place sequences (e.g., mom, map, dad, not) and target words containing variegated place sequences (e.g., mat, dog, cat, nap). Overall, when the target word contained two consonants at the same global place of articulation (e.g., labial-labial, map; coronal-coronal, not), approximately 50% of children's actual productions matched consonant place characteristics. Conversely, when the target word consisted of variegated place sequences (e.g., mat, dog, cat, nap), only about 20% of the productions matched the target consonant sequences. These results suggest that children's actual productions are influenced by their own production abilities as well as by the phonetic forms of target words.

The development of tonal duration in Mandarin-speaking children.

Developmental changes in suprasegmental tonal duration were investigated in monolingual Mandarin-speaking children. Tone durations were acoustically measured in five- and eight-year-old children and adults. Children's tone duration and variability decreased with age. Five-year-olds produced significantly longer tone durations than adults. Adult-like duration patterns existed in all children: Tone 4 was the shortest and tone 3 the longest. Duration differences between tones 2 and 3 became larger between five- and eight-year-olds. Results suggest a prolonged process of tone development beyond establishing phonological contrasts, which can be viewed as a hybrid of physiological production capacities and perceptual learning for maximal contrastivity.

Vowel Context Effects on Consonant Repetition in Early Words.

Purpose Consonant repetitions within words are a well-attested speech error pattern in children's early speech acquisition. We investigated the role of intervening vowel context in understanding speech forms containing consonant repetitions in early words. Intrasyllabic consonant-vowel (CV) sequences within consonant-vowel-consonant (CVC) and consonant-vowel-consonant-vowel (CVCV) forms containing consonant repetitions were analyzed to evaluate whether children's lack of independent movement control for the tongue in word-level sequences might contribute to these observed speech patterns. Method Spontaneous speech data produced by 10 typically developing children learning American English were analyzed longitudinally from the onset of word use to 36 months. Overall patterns and word shape effects for nine CV combinations occurring in their CVC and CVCV word shapes that contained repeated nonadjacent consonants and the intervening vowel were analyzed. Results Three CV combinations-coronal-front vowel, labial-central vowel, and dorsal-back vowel-occurred at above-chance levels. Preference for these CV patterns was strong in CVCV but not in CVC word shapes. These CV combinations occurred frequently at all time periods analyzed for CVCV's while decreasing across time for CVC's. Conclusions Analysis of intrasyllabic patterns within word forms containing consonant repetitions revealed that consonant repetitions in many early words occurred at above-chance levels in the context of articulatorily compatible vowels. Results suggest that children's production system capacities are an important contributing principle accounting for vowel context effects within word forms containing consonant repetitions during earliest speech acquisition.

Non-adjacent consonant sequence patterns in English target words during the first-word period.

The goal of this study was to investigate non-adjacent consonant sequence patterns in target words during the first-word period in infants learning American English. In the spontaneous speech of eighteen participants, target words with a Consonant-Vowel-Consonant (C1VC2) shape were analyzed. Target words were grouped into nine types, categorized by place of articulation (labial, coronal, dorsal) of initial and final consonants (e.g. mom, labial-labial; mat, labial-coronal; dog, coronal-dorsal). The results indicated that some consonant sequences occurred much more frequently than others in early target words. The two most frequent types were coronal-coronal (e.g. dad) and labial-coronal (e.g. mat). The least frequent type was dorsal-dorsal (e.g. cake). These patterns are consistent with phonotactic characteristics of English and infants' production capacities reported in previous studies. This study demonstrates that infants' expressive vocabularies reflect both ambient language characteristics and their own production capacities, at least for consonant sequences in C1VC2 word forms.

A phonetic approach to consonant repetition in early words.

The goal of this study was to evaluate movement-based principles for understanding early speech output patterns. Consonant repetition patterns within children's actual productions of word forms were analyzed using spontaneous speech data from 10 typically developing American-English learning children between 12 and 36 months of age. Place of articulation, word level patterns, and developmental trends in CVC and CVCV repeated word forms were evaluated. Labial and coronal place repetitions dominated. Regressive repetition (e.g., [gag] for "dog") occurred frequently in CVC but not in CVCV word forms. Consonant repetition decreased over time. However, the children produced sound types available reported as being within young children's production system capabilities in consonant repetitions in all time periods. Findings suggest that a movement-based approach can provide a framework for comprehensively characterizing consonant place repetition patterns in early speech development.

Increasing social interaction using prelinguistic milieu teaching with nonverbal school-age children with autism.

PURPOSE: Children with autism display marked deficits in initiating and maintaining social interaction. Intervention using play routines can create a framework for developing and maintaining social interaction between these children and their communication partners. METHOD: Six nonverbal 5- to 8-year-olds with autism were taught to engage in social interaction within salient play routines. Prelinguistic milieu teaching (PMT) techniques were used to teach the children to communicate intentionally during these routines. Intervention focused on the children's social interaction with an adult. The effects of intervention were evaluated using a multiple baseline design across participants. RESULTS: At study onset, the participants demonstrated few consistent interaction with others. With intervention, all of the children improved their ability to sustain social interactions, as evidenced by an increase in the number of communicative interactions during play routines. Participants also increased their overall rate of initiated intentional communication. CONCLUSION: Development of intentional prelinguistic communication within salient social routines creates opportunities for an adult to teach social and communication skills to young school-age children with autism who function at a nonverbal level.

The influence of phonetic complexity on stuttered speech.

The primary purpose of this study was to re-examine the influence of phonetic complexity on stuttering in young children through the use of the Word Complexity Measure (WCM). Parent-child conversations were transcribed for 14 children who stutter (mean age = 3 years, 7 months; SD = 11.20 months). Lexical and linguistic factors were accounted for during the analysis. Results indicate that phonetic complexity, as measured by WCM, did not exhibit a significant influence on the likelihood of stuttering. Findings support previous data that suggest stuttering in preschool-age children does not appear significantly related to phonetic complexity of the production.

Accuracy of consonant-vowel syllables in young cochlear implant recipients and hearing children in the single-word period.

PURPOSE: Attaining speech accuracy requires that children perceive and attach meanings to vocal output on the basis of production system capacities. Because auditory perception underlies speech accuracy, profiles for children with hearing loss (HL) differ from those of children with normal hearing (NH). METHOD: To understand the impact of auditory history on emergence of speech capacities, the authors compared consonant-vowel (CV) syllable accuracy in early words in 4 NH children and 4 children with HL who received cochlear implantation (CI) before age 2 years. Participants were video-recorded monthly for 6 months following word onset. CV vocalizations were coded perceptually with broad phonetic transcription. Observed-to-expected ratios of CV productions and accuracy were tested with chi-square analysis. An ordered multinomial model tested level of accuracy, including both accuracy and error patterns. RESULTS: Most frequently produced sequences were most accurately produced across group and time. NH children were more accurate overall than children with CI. Both groups improved accuracy over time by decreasing partially accurate productions (accurate consonant-inaccurate vowel). Both groups favored CV patterns with compatible place of articulation between consonant and vowel in absolute frequency and level of accuracy. CONCLUSION: Differences in emergence of CV syllable accuracy arise from differences in auditory perception between the NH and CI groups.

Segmental distribution patterns of English infant- and adult-directed speech.

This study compared segmental distribution patterns for consonants and vowels in English infant-directed speech (IDS) and adult-directed speech (ADS). A previous study of Korean indicated that segmental patterns of IDS differed from ADS patterns (Lee, Davis & MacNeilage, 2008). The aim of the current study was to determine whether such differences in Korean are universal or language-specific. Results indicate that consonant distribution patterns of English IDS were significantly different from English ADS. Speakers who used IDS produced fewer fricatives, affricates, nasals and liquids, but more stops and glides, than speakers who used ADS. In terms of vowels, IDS speakers produced more high-back vowels /u / and /open oI/ diphthongs than ADS speakers. These results indicate both general trends and language-specific segmental distribution patterns in IDS. When compared to previous findings on ADS and IDS in Korean, these results for English give support to a more general assertion that segmental distribution patterns in IDS seem to be mediated by linguistic and cultural factors across languages.

Producing American English vowels during vocal tract growth: a perceptual categorization study of synthesized vowels.

PURPOSE: To consider interactions of vocal tract change with growth and perceived output patterns across development, the influence of nonuniform vocal tract growth on the ability to reach acoustic-perceptual targets for English vowels was studied. METHOD: Thirty-seven American English speakers participated in a perceptual categorization experiment. For the experiment, an articulatory-to-acoustic model was used to synthesize 342 five-formant vowels, covering maximal vowel spaces for speakers at 5 growth stages (from 6 months old to adult). RESULTS: Results indicate that the 3 vowels /i u ae/ can be correctly perceived by adult listeners when produced by speakers with a 6-month-old vocal tract. Articulatory-to-acoustic relationships for these 3 vowels differ across growth stages. For a given perceived vowel category, the infant's tongue position is more fronted than the adult's. Furthermore, nonuniform vocal tract growth influences degree of interarticulator coupling for a given perceived vowel, leading to a reduced correlation between jaw height and tongue body position in infantlike compared with adult vocal tracts. CONCLUSION: Findings suggest that nonuniform vocal tract growth does not prevent the speaker from producing acoustic-auditory targets related to American English vowels. However, the relationships between articulatory configurations and perceptual targets change from birth to adulthood.

The emergence of segmental accuracy in young cochlear implant recipients.

In the first steps toward intelligible speech, children must match sounds they can produce with salient word targets from their environment. Differences in auditory history between normal-hearing children (NH) and children receiving cochlear implants (CI) before the age of 24 months afford examination of the production system and auditory perceptual effects on the emergence of early segmental accuracy. Consonant and vowel inventories, accuracy and error patterns during the single-word period were examined in four NH and four CI children. NH and CI groups differed significantly on consonant accuracy, shifting from omissions to correct productions. Vowel productions improved from partially correct to correct. Both groups improved over time and showed similar patterns for segmental accuracy. Results suggest resilience of the production system to differences in auditory history.

English speech sound development in preschool-aged children from bilingual English-Spanish environments.

PURPOSE: English speech acquisition by typically developing 3- to 4-year-old children with monolingual English was compared to English speech acquisition by typically developing 3- to 4-year-old children with bilingual English-Spanish backgrounds. We predicted that exposure to Spanish would not affect the English phonetic inventory but would increase error frequency and type in bilingual children. METHOD: Single-word speech samples were collected from 33 children. Phonetically transcribed samples for the 3 groups (monolingual English children, English-Spanish bilingual children who were predominantly exposed to English, and English-Spanish bilingual children with relatively equal exposure to English and Spanish) were compared at 2 time points and for change over time for phonetic inventory, phoneme accuracy, and error pattern frequencies. RESULTS: Children demonstrated similar phonetic inventories. Some bilingual children produced Spanish phonemes in their English and produced few consonant cluster sequences. Bilingual children with relatively equal exposure to English and Spanish averaged more errors than did bilingual children who were predominantly exposed to English. Both bilingual groups showed higher error rates than English-only children overall, particularly for syllable-level error patterns. All language groups decreased in some error patterns, although the ones that decreased were not always the same across language groups. Some group differences of error patterns and accuracy were significant. Vowel error rates did not differ by language group. CONCLUSION: Exposure to English and Spanish may result in a higher English error rate in typically developing bilinguals, including the application of Spanish phonological properties to English. Slightly higher error rates are likely typical for bilingual preschool-aged children. Change over time at these time points for all 3 groups was similar, suggesting that all will reach an adult-like system in English with exposure and practice.

Segmental properties of input to infants: a study of Korean.

Segmental distributions of Korean infant-directed speech (IDS) and adult-directed speech (ADS) were compared. Significant differences were found in both consonant and vowel patterns. Korean-speaking mothers using IDS displayed more frequent labial consonantal place and less frequent coronal and glottal place and fricative manner. They showed more use of mid and low central vowels in IDS as well as more use of language-specific Korean phonemes. Mothers produced significantly more fortis and geminate and less lenis consonant phonemes in IDS than in ADS. Findings suggest that Korean mothers speaking to infants in the IDS speech style use sounds that more closely match infant production propensities as well as highlighting perceptually salient properties. IDS may serve to facilitate infant learning of ambient language phonological regularities.

Frame dominance in infants with hearing loss.

PURPOSE: According to the frames then content (f/c) hypothesis (P. F. MacNeilage & B. L. Davis, 1990), the internal structure of syllables with consonant plus vowel structure (CV) during canonical babbling is determined primarily by production system properties related to rhythmic mandibular oscillations (motor frames). The purpose of this study was to evaluate whether auditory sensitivity affects the internal organization of CV syllables in infants identified in the 1st year of life with hearing loss. METHOD: CV co-occurrence patterns were analyzed for 13 infants with varying degrees of hearing sensitivity (normal hearing [n = 4], mild-to-moderately severe hearing loss (n = 6), and severe-to-profound hearing loss [n = 3]). Consonants and vowels within CV syllables were grouped according to place of articulation. Thus, an inventory of CV syllables with labial, coronal, and dorsal consonant onsets was created. RESULTS: 77% of predicted frames were confirmed above chance. Additionally, there was no association between pure-tone average and any CV co-occurrence. Finally, co-occurrences that were not predicted by the hypothesis were statistically confirmed in very few instances. CONCLUSIONS: Auditory sensitivity may not influence intrasyllabic organization within CV syllables once infants begin canonical babbling, as the co-occurrences observed are primarily those predicted by the f/c hypothesis.

Characteristics of the rhythmic organization of vocal babbling: implications for an amodal linguistic rhythm.

Vocal babbling involves production of rhythmic sequences of a mouth close-open alternation giving the perceptual impression of a sequence of consonant-vowel syllables. Petitto and co-workers have argued vocal babbling rhythm is the same as manual syllabic babbling rhythm, in that it has a frequency of 1 cycle per second. They also assert that adult speech and sign language display the same frequency. However, available evidence suggests that the vocal babbling frequency approximates 3 cycles per second. Both adult spoken language and sign language show higher frequencies than babbling in their respective modalities. No information is currently available on the basic rhythmic parameter of intercyclical variability in either modality. A study of reduplicative babbling by 4 infants and 4 adults producing reduplicated syllables confirms the 3 per second vocal babbling rate, as well as a faster rate in adults, and provides new information on intercyclical variability.

'Frame dominance' and the serial organization of babbling, and first words in Korean-Learning infants.

Korean-learning infant patterns in babbling and single words were compared with those of English-learning infants and with Korean adult-directed and infantdirected speech to evaluate the roles of intrinsic production constraints proposed by the frame dominance hypothesis versus early learning mechanisms based on input regularities. Intrasyllabic patterns in babbling of Korean-learning infants were like those of English-learning infants. These patterns were not present in Korean infant-directed speech, providing evidence for the assertion that they are intrinsic to infants, and not triggered by input. Unlike English-learning infants, however, Korean-learning infants did not show the expected intrasyllabic patterns in their first words, suggesting that the intrinsic constraints can be overcome in first words if they conflict with ambient speech patterns as they do in Korean. Intersyllabic patterns of Korean-learning infants were mostly similar to those of English-learning infants, showing preferences for consonant manner and vowel height variegation in babbling though only a vowel variegation preference in words. Some implications of the results for generative phonology are considered.

Auditory sensitivity and the prelinguistic vocalizations of early-amplified infants.

PURPOSE: Vocalization development has not been studied thoroughly in infants with early-identified hearing loss who receive hearing aids in the 1st year of life. This study sought to evaluate the relationship between auditory sensitivity and prelinguistic vocalization patterns in infants during the babbling stage. METHOD: Spontaneous vocalizations of 15 early-identified infants with varying degrees of hearing sensitivity, from normal to profound hearing loss, were audiotaped and perceptually transcribed. Associations between the infant's unaided pure-tone average and the following vocalizations were explored: canonical babbling ratio, percentage of utterances containing canonical syllables, canonical syllable shapes, number of syllable sequences, and consonant-onset patterns in canonical syllables. RESULTS: Hearing sensitivity was significantly associated with the percentage of utterances containing canonical syllables, the vocalization types used in utterances, and canonical syllable shapes used by the infants. CONCLUSIONS: Auditory sensitivity contributes significantly to the emergence of babbling patterns. In addition, there is a need for continued study of the vocalizations of infants with milder forms of hearing loss, because in this study, their vocalizations were highly variable despite having received early amplification.

Consonant and syllable structure patterns in childhood apraxia of speech: developmental change in three children.

UNLABELLED: Changes in consonant and syllable-level error patterns of three children diagnosed with childhood apraxia of speech (CAS) were investigated in a 3-year longitudinal study. Spontaneous speech samples were analyzed to assess the accuracy of consonants and syllables. Consonant accuracy was low overall, with most frequent errors on middle- and late-developing sounds. Omissions and substitutions were the dominant error types. Analysis of syllables revealed higher frequencies of error on complex mono- and polysyllables. Multiple regression analyses revealed that consonant accuracy is predicted by syllable shape accuracy and polysyllable frequency. Improvement was noted over time, although irregular patterns of consonant and syllable-level errors persisted across the period studied. Findings suggest that consonant errors in CAS are related to syllable-level deficits, namely difficulty constructing syllabic frames for speech production targets. LEARNING OUTCOMES: On the basis of this article, the reader will be able to (1) describe the deficits in consonant production demonstrated by the participants, (2) analyze the relationship between consonant production and syllable-level patterns of error and (3) consider the value of addressing syllable construction as a therapeutic goal.