The early development of vocalic and consonantal production in Mandarin-learning infants was studied at the transition from babbling to producing first words. Spontaneous vocalizations were recorded for 24 infants grouped by age: G1 (0 ; 7 to 1 ; 0) and G2 (1 ; 1 to 1 ; 6). Additionally, the infant-directed speech of 24 caregivers was recorded during natural infant–adult interactions to infer language-specific effects. Data were phonetically transcribed according to broad categories of vowels and consonants. Vocalic development, in comparison with reports for children of other linguistic environments, exhibited two universal patterns: the prominence of [ɛ] and [ə], and the predominance of low and mid vowels over high vowels. Language-specific patterns were also found, e.g. the early appearance and acquisition of low vowels [ɑ]. Vowel production was similar in G1 and G2, and a continuum of developmental changes brought infants' vocalization closer to the adult model. Consonantal development showed two universal patterns: labials and alveolars occurred more frequently than velars; and nasals developed earlier than fricatives, affricates and liquids. We also found two language-specific patterns: alveolars were more prominent than labials and affricates developed early. Universal and language-specific characteristics in G1 continued to be prominent in G2. These data indicate that infants are sensitive to the ambient language at an early age, and this sensitivity influences the nature of their vocalizations.

This investigation examined phonetic variation in multisyllable babbling of infants from 0;7 to 0;11. The basis of this investigation was to examine assumptions present in major models of infant vocal development which suggest systematic developmental increases in phonetic variation of these babbles, and posit separate stages of repetitive (multisyllables with non-varied phonetic elements) and non-repetitive (phonetically varied multisyllables) babbling. Eight infants were audiotaperecorded in their homes at ages 0;7, 0;9 and 0;11. The multisyllable vocalizations were categorized based on the presence or absence of phonetic variation, and the source of that variation (place change, manner change or both). Multisyllables were produced with phonetic variation at or near the beginning of multisyllable babbling, which failed to support the existence of distinct stages of repetitive and nonrepetitive babbling.

Early prosodic development (f0 variation) was systematically measured in Mandarin-learning infants at the transition from babbling to producing first words. Spontaneous vocalizations of twenty-four infants aged 0 ; 7 to 1 ; 6 were recorded in 45-minute sessions. The speech production of twenty-four caregivers was also audio-recorded during caregiver–infant natural daily interactions at home. All recordings were transcribed using broad prosodic patterns. Analysis revealed four major findings: (1) falling f0 contours were more prominently produced than level and rising contours; (2) high prosodic patterns occurred more frequently than mid and low prosodic patterns; (3) these distribution patterns of f0 contours showed significant similarities in babbling and early words; and (4) these distribution patterns were also similar in infants' and their caregivers' data.

Most studies on CV co-occurrence patterns in early phonetic development have been based on Indo-European languages. Data from infants learning Mandarin, which has a substantially different phonological system from Indo-European languages, can confirm or refute the findings of previous studies, thus shedding further light on the theoretical bases of CV association. Spontaneous vocalizations were recorded in 45-minute sessions for each of 24 Mandarin-learning infants aged 0;7 to 1;6. In addition, the speech production of 24 caregivers was audio-recorded during their natural daily interactions with the infants at home. Both infants' vocalizations and adults' speech were transcribed and analysed for consonant–vowel co-occurrence patterns. These patterns were similar to those in other language groups, but language-specific patterns were evident by 1;0. Combinations of alveolars+front vowels and velars+back vowels confirm Davis & MacNeilage's (1990, 1995) frame-then-content theory and Clements's (1991) model of unified features for consonants and vowels. However, our finding of a language-specific pattern (labials+back vowels) suggests the need to reexamine the ‘pure frame’ of Davis & MacNeilage and Clements's grouping of labials and rounded vowels.