Anticipatory coarticulation in aphasia: effects of utterance complexity

The magnitude and extent of anticipatory coarticulation were examined in groups of fluent and nonfluent aphasic patients and normal control subjects. One- and two-syllable target utterances were elicited at slow and fast rates of speech with or without a consonant intervening between the target consonant and vowel, and with or without a preceding schwa, to manipulate utterance complexity. Acoustic analyses (F2 and centroid frequencies) revealed that both groups of aphasic patients exhibited relatively normal patterns of anticipatory coarticulation. However, small but significant differences among the groups emerged in certain conditions. Surprisingly, increased utterance complexity was not found to reduce coarticulatory effects to a greater degree in the nonfluent relative to the fluent aphasic group. Perceptual tests largely confirmed the acoustic analyses.