The question of whether a syllable constitutes a planning unit in speech production was investigated with naturalistic slips of the tongue in Mandarin Chinese. The corpus was 120 tape-recorded radio programs, each lasting 40 minutes long. It contained approximately 960,000 words and 1314 errors, an error rate of 1 error per 730 words. Among these, 191 were contextual sound errors. To avoid ambiguity in interpretation, a syllable movement error was defined as one in which the target and the source syllable do not share the tone or any syllable constituents and the source syllable moves without carrying its tone with it. Altogether, there were 10 such errors in the corpus, seven anticipatory, two perseverative, and one exchange. Four syllable movement errors were also independently reported by Shen (1992). The probability that the ten errors in our corpus were the result of the syllables slipping far exceeds the probability that they were the result of the syllable constituents (e.g., initial and final) simultaneously and independently slipping. It is concluded that the syllable in Mandarin Chinese is represented and processed as a planning unit in the form of a stored chunk. This contrasts with the dominant view of the syllable's role in English. Several explanations are offered to account for the differential findings in English and in Mandarin Chinese. Recent thoughts and experimental studies on syllables and their relevance to the present study are also discussed.

Key words: speech production, Mandarin Chinese, syllable, slips of the tongue