2016 Volume 12 Issue 4 Pages 35-51
This study examines the ambiguous pitch accents seen in the areas of northeast Tokyo, west Chiba, and east Saitama. In order to clarify the actual situation of these areas, a speaker classification was carried out with 30 speakers from this region, along with 7 speakers from the central Tokyo area, for a total of 37 speakers. This classification was based on the acoustic features of drop range and relative peak. Using cluster analysis, the speaker groups were classified based on appearance trends of those acoustic features into three groups: “clear pitch separation,” “unclear high-low pitch separation,” and “unclear form differentiation.” Analyzing these acoustic features in detail, the “clear pitch separation” group displays a large drop range and a large distance between relative peak positions. On the other hand, the two “unclear” groups show a small separation between high and low pitches, and particularly the “unclear form differentiation” group displays an additional special characteristic of—in addition to the small separation between high and low pitches—a small distance between relative peak positions. The classified speaker groups were then overlaid on a map in order to visualize the variations between individual speakers that are a special characteristic of ambiguous pitch accents. Finally, by positioning each group discovered in analysis according to high-low pitch difference and classification level of decline positions, the accent change in this region was reinterpreted as the interlinking connections of multiple acoustic features.
