Acoustic evidence for positional and complexity effects on children's production of plural -s.

PURPOSE: Some variability in children's early productions of grammatical morphemes reflects phonological factors. For example, production of 3rd person singular -s is increased in utterance-final versus utterance-medial position and in simple versus cluster codas (e.g., sees vs. hits). Understanding the factors that govern such variability is an important step toward modeling developmental processes. In this study, the authors examined the generality of these effects by determining whether position and coda complexity influence production of plural -s, which phonologically manifests the same as 3rd person singular -s.
METHOD: The authors used an elicited imitation task to examine the speech of 16 two-year-olds. Eight plural nouns (half contained simple codas, half contained cluster codas) were elicited utterance-medially and utterance-finally. Acoustic analysis of each noun was used to identify acoustic cues associated with coda production.
RESULTS: Results showed that plural production was more robust in utterance-final versus utterance-medial position but equally robust in simple versus cluster codas.
CONCLUSIONS: These findings extend positional effects on morpheme production to plural -s. An effect of coda complexity was not observed for plural but was observed for 3rd person singular, which raises the possibility that the morphological representation proper influences the degree to which phonological factors affect morpheme production.