  We propose a physical model of speech to explain its precision and
robustness. We begin by reducing the dynamics to the bare minimum of polygonal
billiards. The symbolic stability of the billiard trajectories against
variations in action and the oral cavity geometry forms the basis for precision
and robustness in articulation. This stability survives forcing and dissipation
to underpin reliable encoding of the trajectories into acoustic emissions. The
kinematics of oral billiards and the cyclical nature of the forcing mechanism
engender a grammar of the syllable independent of any language. The symbolic
dynamics of oral billiards is rendered nearly maximally observable by their
concomitant acoustic emissions. Speech recognition is the set of computations
on the sub-maximally informative acoustic observables from which the symbolic
dynamics of oral billiards may be inferred.
