On the nature of Tone 4 alternation in Taiwan Mandarin: Insights from acoustic analysis of trisyllabic right-branching word productions

Abstract

Tone 4 (T4) alternations refer to the phenomenon where the tone values of a T4 syllable reduces from ‘51' to ‘53' when it is followed by another T4 syllable in Mandarin Chinese. It is inconclusive if the nature of T4 alternations is tone sandhi (an abstract phonological rule) (Chao, 1948; Jang, 2021) or tonal coarticulation (an articulatory phenomenon in speech production) (Lin, 20007; Shen, 1990). The current study invited 30 Taiwan Mandarin speakers to produce 10 pairs of right-branching trisyllabic words, including sequences of [T4[T4-T4]] (e.g., dà diàn shì 'big television') and [T4[T4-Tone1]] syllables (e.g., dà diàn jiā ‘big store'). The T4 sandhi view predicted that the surface tone values of the first syllables in these two sequences would differ (“51i” vs. “53”), while the T4 coarticulation view predicted that the tone values would be the same (“53”). Results from the acoustic analysis on fundamental frequency (f0) contour, f0 slope and vowel length of the first T4 syllables indicated that the differences were not statistically significant. These results supported the tonal coarticulation view. Discussions pertaining to the mental grammar for the tone value distances of two adjacent T4 syllables and the typology of tonal coarticulation in Mandarin Chinese are formulated.