Sequences of phonemic approximations in a Thai conduction aphasic.

Sequences of phonemic approximations (SPAs) to a single target word on a picture naming task were investigated in a Thai-speaking conduction aphasic. A corpus of 207 SPAs was analyzed with an adaptation of Valdois, Joanette, and Nespoulous's (1989) methodology to a tone language. Measures included the length of SPAs, overall degree of approximation to the target of the last attempt and each of the preceding attempts, as well as degree of approximation to the target in terms of number of syllables, syllable structure, segments (consonants/vowels), and tones. Results indicated that there was a steady progression toward the target regardless of eventual outcome or length of sequence. Number of syllables of the target word was better preserved than syllable structure, and tones better than segments. In the course of SPAs, tonal information was accessed earlier than segmental, and syllabic length information earlier than syllabic structure. Within SPAs, tonal information was more stable than segmental across successive approximations. Findings are discussed in relation to a functional model of single word production and multidimensional phonological representations.