Speech timing in Thai left- and right-hemisphere-damaged individuals.

An acoustic analysis of syllable duration in short Thai phrases was conducted to evaluate the effects of focal brain damage on the control of speech timing. Almost all 35 of the subjects had participated in each of four previous companion studies: 13 left-brain-damaged (6 nonfluent aphasics; 7 fluent aphasics), 14 right-brain-damaged patients, and 8 normal controls. Somewhat surprisingly, results revealed relatively normal timing patterns in 3-syllable phrases in all subject groups. A comparison of the current study and the four others, however, led us to conclude that Thai-speaking nonfluent aphasics exhibit a speech timing deficit regardless of the linguistic level of representation, whereas timing deficits in fluent aphasics appear to be restricted to units larger than a syllable. Speech timing, on the other hand, appears to be intact across the board in right-brain-damaged individuals. Findings are brought to bear on theories of temporal control in brain-damaged patients.