Speech prosody, just like the segmental aspect of speech, conveys communicative meanings by encoding functional contrasts. The contrasts are realized through articulation, a biomechanical process with specific constraints. Prosodic phonology or any other theory of prosody therefore cannot be autonomous from either communicative functions or biophysical mechanisms. Successful modeling of speech prosody can be achieved only if communicative functions and biophysical mechanisms are treated as the core rather than the margins of prosody.