178 Terumi Imai
be devoiced in Japanese as in [NLલWD] ‘north’ and [WVXલWߑL] ‘soil.’ There are dif-
ferent approaches to this phenomenon, but most phoneticians agree that it
occurs because of the overlap of the glottal gestures: the glottis is open for
the preceding voiceless consonant and the following consonant, but in order
to produce a voiced vowel, the glottis must be closed. This movement of the
glottis—open, closed, open again—requires more effort than keeping it open
and therefore causes the devoicing of the vowel. Thus, a devoiced vowel is a
vowel produced while the glottis is open. A completely devoiced vowel does
not show a periodic wave, has no clear formants in a spectrogram, shows a
drop in intensity and no pitch track, and there is no audible voicing, although
there is mora preservation.
Here are some examples: Figures 6.1 and 6.2 show two tokens of a same
word, /see+katsu#hi/ ‘living expenses,’ produced by different speakers. Fig-
ure 6.1 shows the token with a voiced vowel and Figure 6.2 with a devoiced
vowel. The upper window shows the sound wave and the lower window shows
the spectrogram. The thick black dotted line in the middle of the spectrogram
shows the pitch track, and the thin white line above the pitch track shows the
intensity. In Figure 6.1, the periodic wave for /u/ in the third syllable is rather
small compared to others, but we can still see the clear formants for the vowel
/u/. There is a clear pitch track, which remains stable until it reaches the ¿ nal
syllable. Intensity also rises where the vowel /u/ is produced. Thus, we can say
all the four vowels in this word are voiced.
Figure 6.1 /see+katsu#hi/ (‘living expenses’) with a voiced vowel.