A corpus-based investigation of pitch contours of monosyllabic words in conversational Taiwan Mandarin

In addition, Chuang et al. (2024) recently reported that the tonal contours of disyllabic Mandarin words with T2-T4 tone pattern are co-determined by their meanings. Following up on Chuang et al. (2024) research, we present a corpus-based investigation of how the pitch contours of monosyllabic words are realized in spontaneous conversational Mandarin, focusing on the effects of contextual predictors on the one hand, and the way in words' meanings co-determine pitch contours on the other hand. We analyze the F0 contours of 3824 tokens of 63 different word types in a corpus of spontaneous conversational Taiwan Mandarin, using the generalized additive (mixed) model to decompose a given observed pitch contour into a set of component pitch contours. These component pitch contours isolate the contributions to the pitch contour of the variables taken into account in the statistical model. We show that the tones immediately to the left and right of a word substantially modify a word's canonical tone. Once the effect of tonal context is controlled for, the canonical rising (T2) and dipping (T3) tones emerge as low flat tones, contrasting with T1 as a high tone, and with T4 as a high-to-mid falling tone. The neutral tone (T0), which in standard descriptions is taken to primarily depend for its realization on the preceding tone, emerges as a low tone in its own right, the realization of which is modified by the other predictors in the same way as the standard tones T1, T2, T3, and T4. In line with the results from a previous study on disyllabic words with the T2-T4 tonal contour (Chuang et al., 2024), we also show that word, and even more so, word sense, co-determine words' F0 contours, and that, as a consequence, heterographic homophones (e.g., 的, 得, and 地) have their own tonal signatures. Analyses of variable importance using random forests further supported the substantial effect of tonal context and an effect of word sense that is almost as important as that of tonal context.