Imitation of synthesized English and nonEnglish vowels by children and adults

Imitations of 15 synthesized vowels, some like English vowels and some not, were obtained from nine adults and ten 6-year-old children. Estimates of the first three formant frequencies (F₁, F₂, and F₃) were made from spectrograms of the vowel imitations. The reliability of reproduction was assessed by calculating standard deviations for five imitations each of ten of the synthetic stimuli. Generally, both the intrasubject and intersubject variabilities were greater for the children than for the adults. However, the differences in intrasubject variability between the two groups often were not much greater than the difference in measurement error which would be expected for voices of different fundamental frequencies. Subjects tended to reproduce the nonEnglish vowels less reliably than the English vowels, although the adults were less influenced by phonetic familiarity than were the children. Vowel familiarity appeared to be especially important for reliable reporoduction of the F₂ frequency. Plotting of the imitation data for English vowels in a F₁–F₂ plane with linear dimensions revealed a fairly systematic clustering for the four age-sex groups of men, women, boys, and girls, but the group clustering was not so systematic for the imitation data for the nonEnglish vowels.This work was supported by Public Health Service Research Grant NS-HD-12281.