Effects of lexical meaning and practiced productions on coarticulation in children's and adults' speech.

This investigation examined the effect of familiarity with a speech target on the magnitude of the coarticulation observed in children (aged 3, 5, and 7 years) and adults. For the purposes of this investigation, coarticulation was defined as the effect that a following vowel, /i/ or /u/, had on the frequency value of the second formant (F2) in the preceding fricative, /s/ or /f/. Familiarity with the spoken targets was examined through the manipulation of two factors: (a) the presence or absence of lexical meaning and (b) the extent to which speakers were allowed to practice an item prior to recording. Results of acoustic measurements confirm that the children exhibited a greater effect of a following vowel on the preceding fricative when compared to adults. Nonmeaningful production items appeared to exhibit a greater effect of the vowel on the preceding fricative than meaningful production items, regardless of age of the individual. Limited motor practice did not have an effect on degree of fricative-vowel coarticulation in production items for any of the age groups. For the productions in this investigation, the primary coarticulatory effect was intrasyllabic.