We present an acoustic study of segmental and prosodic properties of words produced by a female speaker of Chinese with left-hemisphere brain damage. We measured the location of the point vowels /a, e, @?, i, y, o, u/ and determined their separation in the vowel plane, and their perceptual distinctivity. Similarly, the acoustic properties of the four lexical tones were measured in the F0 x time space. The data for our brain-damaged speaker were compared with those of a healthy control speaker. Results show that the patient's vowels hardly suffered from her lesion (relative to the vowel dispersion in the healthy control speaker), but that the identifiability of the four lexical tones was greatly compromised. These findings show that the tonal errors in aphasic speech behave independently of the segmental errors, even though both serve to maintain lexical contrasts in Chinese, and are therefore part of the lexical specification of Chinese words. The present study suggests that the specification of segmental and tonal aspects of lexical entries in Chinese, and in tone languages in general, are located or processed separately in the brain.