Fig. 1.

Average TA/CT activity ratios for vowel [a:] and phonation into 30-cm tube (a), vowel [a:] and voiced bilabial fricative [β:] (b) and phonation into 30-cm tube, straw and stirrer and on [β:] (c). Vowel derived from [pa:] syllables produced at comfortable loudness and loud before phonation into the tube and production of the fricative and at comfortable loudness and controlled loudness after the tube and the fricative. Since there was no significant difference in the vowels produced at different loudness levels before and after the fricative, the average values are given. All values are presented relative to the highest.