Search

Purpose: As a class, fricatives are more 'resistant' to consonant-vowel coarticulation than other English sounds. This study investigates the relative coarticulatory resistance of /0, s, /[??] in child and adult speech to better understand the acquisition of individuated speech sounds. Method: Ten 5-year-old children, seven 8-year-old children, and nine college-age adults produced [eFV] sequences in carrier phrases, where F was /0/, /s/, or /[??]/ and V was /ae/, /i/, or /u/. In Experiment 1, coarticulation was perceptually indexed: 65 adults predicted the target stressed vowel based on forward-gated audiovisual speech samples for a subset of four speakers from each age group. In Experiment 2, dynamic spectral measures of the /eFV/ sequences were analyzed using smoothing spline analysis of variance to again test for vowel effects on fricative articulation across age groups. Results: The perceptual results indicated that fricatives blocked vowel-vowel coarticulation across speaker age groups. Contrary to expectation, vowels were most accurately predicted when F was /s/ and not when it was /[??]/ or /0/ across age groups. Acoustic results indicated the expected biomechanically motivated /[??]/ > /s/ > /0/ coarticulatory resistance hierarchy in adults' speech. By contrast, /[??]/ > /s/ were similarly influenced by context in 8-year-olds' speech, and the results from 5-year-olds' speech suggested an influence of order of acquisition in that /0/ was surprisingly resistant to coarticulation. Conclusion: The study results are taken to suggest that a temporal constraint on fricative articulation interacts with biomechanical constraints during development to influence patterns of coarticulation in school-age children's speech., Speech sound acquisition is typically approached from a phonemic perspective (e.g., Dodd et al., 2003; Prather et al., 1975; Smit et al., 1990). Studies focus on how children do or [...]

Purpose: Liquids are among the last sounds to be acquired by English-speaking children. The current study considers their acquisition from an articulatory timing perspective by investigating anticipatory posturing for /l/ versus /[??]/ in child and adult speech. Method: In Experiment 1, twelve 5-year-old, twelve 8-year-old, and 11 college-aged speakers produced carrier phrases with penultimate stress on monosyllabic words that had /l/, /[??]/, or /d/ (control) as singleton onsets and /ae/ or /u/ as the vowel. Short-domain anticipatory effects were acoustically investigated based on schwa formant values extracted from the preceding determiner (= the) and dynamic formant values across the /[??]#LV/ sequence. In Experiment 2, long-domain effects were perceptually indexed using a previously validated forward-gated audiovisual speech prediction task. Results: Experiment 1 results indicated that all speakers distinguished /l/ from /[??]/ along F3. Adults distinguished /l/ from /[??]/ with a lower F2. Older children produced subtler versions of the adult pattern; their anticipatory posturing was also more influenced by the following vowel. Younger children did not distinguish /l/ from /[??]/ along F2, but both liquids were distinguished from /d/ in the domains investigated. Experiment 2 results indicated that /[??]/ was identified earlier than /l/ in gated adult speech; both liquids were identified equally early in 5-year-olds' speech. Conclusions: The results are interpreted to suggest a pattern of early tongue-body retraction for liquids in /[??]#LV/ sequences in children's speech. More generally, it is suggested that children must learn to inhibit the influence of vowels on liquid articulation to achieve an adultlike contrast between /l/ and /[??]/ in running speech., The coarticulatory patterns of children's speech are compatible with the hypothesis of whole word speech production (Nittrouer et al., 1989; Redford, 2019). The hypothesis begs the question of how children [...]