ABSTRACT
If we try to map vocalic products with reference to the volume of the oral front cavity, we distinguish first between a maximum, when lip protrusion combines with a retraction of the mass of the tongue, and a minimum, when lip retraction is accompanied by the fronting of that mass. The opposition between the two is optimal for the minimal vocalic apertures corresponding to [u1 and [i1. For the maximal aperture noted by means of various shapes of the letter a, it gets blurred: the front cavity is no longer distinct from the oral cavity as a whole and lip rounding and lip retraction are less easy to contrast.
