The effect of intonation on pitch realization of the tones in Chinese Putonghua

Pitch realization of the four tones in Chinese Putonghua is investigated acoustically on the levels of tone category, location in sentence and accent pattern. In the experiment, the target words containing target tones were embedded in three kinds of sentence focus and two kinds of non-focus positions in the material, and the whole pitch ranges of the words and the high/low points of the target tones were analyzed. The results revealed the complexity of tonal variation under intonational effect. First, Tone 2 was located in the lower register of the tonal range under both focused condition and neutral unfocused condition, and the low point of Tone 4 was close to that of Tone 2 and sometimes higher although the theoretical tonal value of the former was lower than that of later. Secondly, under sentence-initial focus condition, tonal range expanded upward and downward, while under sentence-final condition, the whole tonal range was raised. In addition, the high points of the four tones did not necessarily vary in proportion to the top threshold of the pitch range, and so did the low points of the tones to the bottom threshold. Thirdly, the pitch of a post-focus tone was constrained by its rhythmic relation with the focused tone. When located in a same rhythmic foot, the pitch of the post-focus tone depended on the pitch of the focused tone, and the relationship between the two tones was similar to that between a normally stressed tone and its following neutral tone. Yet, when there was a foot boundary between the focused tone and its following tone, the post-focus tone tended to keep its tonal feature to some extent. These results imply that lots of detailed rules that take focus structure, rhythmic structure, tonal coarticulation and tonal feature into consideration are needed to establish a well-predictive intonation model in Chinese Putonghua.