CONSONANT VOWEL INTERDEPENDENCIES IN BABBLING AND EARLY WORDS - PRELIMINARY EXAMINATION OF A LOCUS EQUATION APPROACH

Consonant-vowel productions at two distinct stages of language develop ment were studied in a single female child. At 12 months canonical bab bling syllables (N = 144) identified by a panel of listeners as compri sing [bV], [dV], and [gv] tokens were acoustically analyzed by measuri ng F2 transition onset and F2 midvowel frequencies and plotting their relationship as locus equations for each stop category. A regression a nalysis performed on these scatterplots revealed differential slopes a nd y-intercepts as a function of stop place. The same analysis was per formed 9 months later on CV utterances (N = 243) produced as syllable- initial segments of real words by the same child. Whereas labial and v elar locus equation parameters moved toward more adult-like values, al veolar slope and y-intercept moved away from adult values and more in the direction of decreased coarticulation between vowel and consonant. There was greater scatter of data points around the regression line f or production of words compared to babbling. These results are compare d to locus equations obtained from 3-5-year-olds and adults. Locus equ ations appear to be useful as an empirical developmental probe to docu ment how CV productions gradually approach adult categorical standards .