A corpus analysis of patterns of age-related change in conversational speech.

Conversational speech from over 300 speakers from 17 to 68 years of age was analyzed for age-related changes in the timing and content of spoken language production. Overall, several relationships between the lexical content, timing, and fluency of speech emerged, such that more novel and lower frequency words were associated with slower speech and higher levels of disfluencies. Speaker age was associated with slower speech and more filled pauses, particularly those associated with lexical selection. Increasing age, however, was also associated with longer utterances and greater lexical diversity. On balance, these analyses present a picture of age-related changes in speech performance that largely support data obtained from controlled laboratory studies. However, particular patterns of age-related change may be moderated in conversational situations.