Glottal closure and perceived breathiness during phonation in normally speaking subjects.

Glottal closure and perceived breathiness were evaluated in 9 female and 9 male normally speaking subjects ranging in age from 20 to 35 years. Phonations of the vowel /i/ at three loudness and pitch levels were performed. The degree of glottal closure was judged by speech clinicians from video-fiberstroboscopic recordings. Later they rated the degree of perceived breathiness both in the vowels recorded during the fiberscopy and in separately tape-recorded vowels. Intra- and interjudge reliabilities were satisfactory. The degree of incomplete glottal closure and the degree of perceived breathiness increased significantly as an effect of decreased loudness. Neither the degree of closure nor the perceived breathiness were significantly affected by changes in pitch or by interaction effects. It was concluded that incomplete glottal closure of the posterior parts of glottis should be regarded as normal primarily in women and that loudness should be taken into consideration when studying glottal closure and breathiness.