Physiological Aspects of Certain Laryngeal Features in Stop Production

Multichannel EMG recordings were made of the instrinsic and extrinsic laryngeal muscles during production of intervocalic labial stops of five phonetic types: explosive voiced inaspirate, implosive voiced inaspirate, voiced aspirate, voiceless inaspirate. and voiceless aspirate. The recorded data, computer processed to obtained average EMG values, indicate that abductor and adductor muscle groups follow coordinated patterns of activity corresponding to opening and closing of the glottis. In particular, the interarytenoid and posterior cricoarytenoid muscles showed reciprocal patterns both in degree and timing of activity. In addition, the sternohyoid showed marked activity for the implosive stop, presumably correlated with an abrupt lowering of the larynx. In a second experiment using the same speaker and the same syllables, motion pictures of the glottis were taken by means of a flexible fiberscope. The overall conclusion suggested is that active adjustments of the glottis in terms of coordinated muscle activity, and the timing of this activity relative to supraglottal events, are the decisive factors by which the various stop consonant types are differentiated. [This research was supported by the National Institute of Dental Research through an NIH grant]