Oral Cavity Enlargement in Retroflex Stops

Abstract

It is generally recognized that front-articulated stops are more compatible with voicing than backarticulated stops because the larger oral volume and compliance of front stops allows for longer trans-glottal airflow. Phonological patterns suggest that retroflex stops may be an exception to this pattern and may be more compatible with voicing than their dental/alveolar counterparts. An experiment was conducted in which an artificial leak was created in three speakers, and the effect of the abrupt closure of this leak on voicing was measured for [b d  ]. The results of this experiment show that [b d ] follow the pattern of longer voicing for more front articulations. The retroflex was an exception – for two speakers voicing for [] persisted longer than for [d], and for one speaker [] voicing persisted longer than for [b d]. We believe that the greater surface area presented by the concave shape of the tongue during retroflexes as compared to dentals/alveolars allows for greater passive cavity expansion (i.e. compliance) and is a possible explanation of the observed pattern.