Intonation and speech timing: Association or dissociation?

A number of prosodic studies on brain damaged patients [e.g., Gandour et al., Brain & Lang. 43, 275–307 (1992)] have concluded that the production of fundamental frequency (F0) is tied to temporal control, and that abnormalities in F0 associated with intonation exhibited by aphasic patients is due to underlying disturbance in speech timing. The present study examined F0 and durational measures in syntactically simple English statements and interrogatives produced by fluent and nonfluent aphasic patients as well as a group of normal subjects. Measures conducted included initial F0 peak (P1), the initial frequency at the terminal region of the F0 contour (TIF), amount of terminal F0 fall/rise, utterance length, duration of terminal F0 fall/rise, and distance between P1 and TIF. Results showed that the nonfluent aphasic patients performed at comparable levels with the normal subjects on all F0 measures, but they were severely impaired across the board on temporal measures. The fluent aphasic patients’ performance on both sets of measures were generally comparable to normal performance, although in absolute terms their durations were also longer than normal. These findings contradict the view that F0 production depends on speech timing. Rather they suggest that the two parameters may be dissociated.