On Acoustic Features Relevant to Tonal Distinction of Myanmar
The purpose of this paper is to examine the acoustic phonetic features of four distinctive tones of Myanmar (Burmese) by measuring their fundamental frequency.
Masuko (2009) has shown the results of measurement of the fundamental frequency, F0 at the initial point and F0 at the final point, of the words with four phonologically distinctive tones that have been described as (1) low-level, (2) high-level, (3) falling and (4) checked tones. The overlapping ranges of F0 in the four tones suggest that sole pitch in the above F0 points is not sufficient to specify the tonal difference.
It is generally assumed that dynamic change of pitch curve reflects physiological state or change of states of glottis: tensioned or relaxed. We further assume that the tonal pitch curve reflects psychological quantity of the tone. In the present study, we examined some pitch-related acoustic features, such as inclination and duration of pitch curve of each tone.
The results are as follows.
(1) The differences in inclination of pitch curve contribute to distinguish three tones: the low-level, high-level and falling tones, except the checked tone.
(2) Along with the inclination of pitch curve, duration, F0 at the initial and final points of the pitch curve is relevant to distinguish each tone. The low-level tone is characterized by F0 at the final point and gradual falling pitch. The high-level tone is specified by gradual rising or falling in the pitch inclination around zero degree, in addition to F0 at the final point being not so low as F0 in the falling tone. The falling tone has steep pitch inclination, which contrasts to the high-level and low-level tones. Its F0 at the final point is as low as that of the low-level tone, which contributes to contrast with the checked and high-level tones. Furthermore, the falling tone has the highest F0 at the initial point, which serves to distinguish it from the low-level and high-level tones. So does the short duration of the falling tone.