Acoustic correlates of [b] and [w] produced by normal young to elderly adults.

Various studies indicate that temporal characteristics of articulated subphonemic segments and syllables change as a function of age. The purpose of the present study was to investigate age-related changes in the production of a phonetic contrast--in particular that of the stop consonant [b] versus the semivowel [w]. Thirty-nine subjects with normal hearing and belonging to three age groups (20-30, 50-60, 70-80 years old) were tested. Acoustic analyses of the recorded syllables [b alpha] and [w alpha] indicated that duration of syllables, prevoicing, release, and vowel transition became significantly longer with the speaker's age, except for the vowel transition in the [w] context. However, acoustic cues, such as the difference in amplitude change in the vicinity of the release segment, were not sensitive to the effects of aging.