Abstract
Results of previous studies examining ambiguous phrases revealed that duration appeared to be the most robust cue in disambiguation in English, while pause was the more powerful cue in Mandarin. The present study investigated from acoustic and perceptual viewpoints how Taiwan Mandarin subjects disambiguate phrases. The experiment was done within a question-answer context. The phonetic realization of three kinds of ambiguous phrases was studied: (1) lexically and syntactically ambiguous phrases with ‘ji’ (how many/ several), (2) lexically ambiguous phrases, and (3) syntactically ambiguous phrases. No systematically significant differences in fundamental frequency and in duration were found for lexically ambiguous phrases and syntactically ambiguous phrases. Despite that, we observed that the syllables might have a significant duration difference in some ambiguous phrases. The perception study confirmed that our subjects could perceive this acoustic difference well. Moreover, the acoustic difference coincided with the syntactic boundary. For the phrases in which no significant acoustic difference was found, the perception correct rate was low and the subjects tended to use the concept of sentence frequency to interpret the ambiguous phrases. We also showed that there might be different duration in Taiwan Mandarin grammatical categories. A word serving as a verb might have a longer duration compared with the same word serving as a noun. Ambiguous phrases provide useful material to understand the correlation between syntactic and prosodic structure. Despite that, English ambiguous phrases were investigated in some previous studies (Lehiste 1973, Lehiste et al. 1976, Macdonald 1976, Streeter 1978), few studies had been done in Mandarin Chinese (Shen 1993). By use of syntactically and lexically ambiguous phrases, Lehiste (1973) and Lehiste et al. (1976) found that the durational cue was more important than pause to disambiguate utterances in English. Instead, Shen (1993), using three small texts composed of syntactically ambiguous phrases, showed that the pause was more powerful cue in Mandarin Chinese. Similar results were obtained from the studies on non-ambiguous phrases: the lengthening of preboundary syllable (Klatt 1975), the insertion of pause at phrase boundaries. (O’Malley et al. 1973, cited by Lehiste et al. 1976) It has been assumed that ambiguous phrases have the same phonetic realization, and listeners disambiguate these phrases with the aid of the context. It is nevertheless noted that no context was included in ambiguous phrases in those studies. In this study we try to address the following issues: (1) Do ambiguous phrases relevant to different contexts have acoustically the same phonetic realization? (2) If the answer is negative, which acoustic cues (fundamental frequency, duration) play the important role to differentiate one structure from the other? (3) Do those acoustic differences coincide with the syntactic boundary? (4) Can Taiwan Mandarin subjects perceive those acoustic differences? This paper consists of two parts. The first one is a study on ‘ji’, a homonym with different grammatical classes (a question marker, and a numeral marker). The other is to investigate 24 pairs of ambiguous phrases.