Current research in the phonetics-phonology interface focuses on levels of phonetic encoding, aiming at generalizations about level-specific preferences for the phonological encoding of certain phonetic parameter values and possible typological conclusions to be drawn from empirical distributions thereof.
As a working basis and heuristic guideline, a simple model of hierarchical prosodic domains is being cross-classified with basic phonetic parameters:
The resulting slots should be filled with phenomena from existing phonological systems and their actual or potential properties. For instance, the parameter of quantity (= duration) is encoded on the utterance level extraphonetically (i.e., the length of an utterance is mainly determined by factors outside phonetics, like semantic intentions of the speaker an so forth) and paralinguistically (i.e., phonetic prolongation of an utterance, like in hesitation phenomena, serves mainly paralinguistic functions). At the bottom of the prosodic hierarchy, on the phone level, the parameter of quantity (= duration) is encoded in terms of the phonetic properties of specific gestures, thus being mainly a product of articulatory movements and their natural limitations: for instance, a flap cannot be lengthened without becoming something else than a flap, due to the ballistic nature of the respective gesture, whereas any vowel and all continuants can be lengthened up to the limit of lung volume exhaustion. A pharyngeal approximant [h] cannot be lengthened to the same degree as an oral fricative due to its higher rate of volume velocity of the airflow, and so forth. Thus, the natural length of different kinds of speech sounds varies considerably, depending on the phonetic mechanisms underlying their respective production gestures.
Some of the slots lend themselves to being filled quite easily, maybe almost trivially, while others turn out to be more problematic.
Suggestions and comments are highly welcome: