Voiced-voiceless distinction in alaryngeal speech - acoustic and articula

In an investigation of the speech of layngedomized speakers we presently focus on their ability to distinguish behoeen voiced and voiceless speech sounds. Some of them are able to produce this distinction clearly in some contexts and it is quite remarkable considering the structure of the pharyngo-esophageal entrance, serving as the post-operative voice source. However, there are a number of acoustic cues that serve to signal the distinction between voiced and voiceless phonemes and an acoustic analysis will tell how this is possible. INTRODUCTION The voiced-voiceless distinction is a typical and common characteristic for most languages of the world and there are numerous pairs of speech sounds that differ in this respect, such as the plosives /p, b/, /t, d/, /k, g/ as well as the fricatives /f, v/, /s, z/, etc. The glottis is well adjusted for rapid devoicing gestures by means of the laryngeal muscles. It is from a theoretical point of view much harder to understand how this articulatory gesture is made by the structures around and within the pharyngo-esophageal segment ("PE-segment"). This part is usually described as less mobile and not easily adjusted by will. However, there are indications that good alaryngeal speakers are quite accurate in signalling voiced/voiceless distinctions and both articulatory and acoustic analyses support this. As part of our investigation of alaryngeal speech we are interested in the mechanism of the alaryngeal voice source. So far, we have analyzed the speech of seven esophageal and seven tracheo-esophageal speakers, two of whom also master esophageal speech. There seems to be a wide variety of voices, in terms of quality, pitch range, phonation stability etc. We believe that part of this variation stems from the fact that this group of speakers anatomically differ a lot as regards the PE-segment, that serves as the voice source, and there is probably a much larger variation than what can be found in the glottal structures.