Comparison of Phonetic Naturalness between Rising-Falling and Falling-Rising Tonal Patterns in Taiwan Mandarin

The new tonal pattern, a falling-rising pitch sequence, emerges from nominal reduplications produced by young children, teenagers, and motherese in Taiwan Mandarin. The pattern implies a child-like speech style and an intimate relationship between speakers and addressees, so application of the pattern usually denotes innocence, ingeniousness, and coyness. The morphophonological pattern sounds like a Tone3 (T3) Tone2 (T2) sequence, a falling-rising pitch contour. The new pattern has an opposite contour of the T2-T3 sequence, a rising-falling contour, which is a phonological output derived from two consecutive T3s based on T3 Sandhi in Mandarin. The study investigated phonetic naturalness of the two tonal patterns in terms of the pitch changes within a monosyllabic domain and the ratio between pitch changes and duration in T2 and T3. Eight Taiwan Mandarin speakers, four males and four females, were recruited to pronounce the two tonal patterns. The current production results showed that the pitch changes of both T2 and T3 syllables in the T3-T2 sequence were significantly fewer than in the T2-T3 sequence, so the new pattern causes fewer articulatory efforts. As a result, the new T3-T2 pattern, a falling-rising sequence, seems more phonetically natural than the T2-T3 pattern, a rising-falling sequence. The results can explain why young Mandarin speakers acquire the T3-T2 pattern earlier than the T2-T3 sequence of the T3 Sandhi.