The Variability in Sound Pattern: From Individual Differences to Sound Change

In a class of introductory phonology, a sound pattern is usually expressed with a rule like A → B / X_Y or a constraint like *XAY. For a real sound pattern, however, there is usually a great variability when it comes to individual speakers and specific phonetic contexts (Labov 1972; Coetzee & Pater 2011). It has been widely argued that such a variation can be a path of sound change (Wang 1969; Yu 2013). The sound pattern to focus in this study is the merge between the dental and palatal sibilants before the vowel [_i], i.e., the neutralization of [si tsi tsʰi] and [ɕi tɕi tɕʰi], which has been widely observed across languages in terms of both language typology and sound change. From 18th century Mandarin to Standard Chinese, for example, the dental sibilants in [si tsi tsʰi] have been palatalized into and thus merged with the palatal sibilants in [ɕi tɕi tɕʰi] (Chen 1976; Wang 1985). To investigate the potential individual differences in such a merging process, the dental vs. palatal sibilants in Xiangtan Chinese is examined, which is reported to fully contrast /s ts tsʰ/ vs. /ɕ tɕ tɕʰ/ in the [_i] context (Zeng 1993) and therefore mirrors the contrastive system of 18 th -century Mandarin before the merger. The hypothesis to test is that there is acoustic variability in the realization of /si tsi tsʰi/ in that some of these syllables are realized as /ɕi tɕi tɕʰi/, which could potentially serve as the seed for future merger. Eleven native female speakers of Xiangtan Chinese were recruited to produce /si tsi tsʰi/, /ɕi tɕi tɕʰi/, as well as /sɹ̩ tsɹ̩ tsʰɹ̩/ (ɹ̩ is syllabic dental approximant) with matched tones. Acoustic measurements of the sibilants were submitted to a series of discriminant analyses, in which a trained classifier was adopted to categorize a dental sibilant from the [_i] context as a dental or palatal sibilant. The results showed that (i) a portion of the sibilants extracted from /si tsi tsʰi/ was categorized as palatals and (ii) some speakers’ production of the sibilant onsets in /si tsi tsʰi/ showed a variation between dental and palatal sibilants. In general, this study shows categorical variation in the realization of the dentals in the [_i] context as either dentals or palatals, which could potentially lead to a merger that recapitulates the one that occurred in 18th century Mandarin. The results therefore support the view that variation could be a path to sound chang.