ABSTRACT
In the previous chapters, I have presented a system of constraints which captures certain generalizations concerning lenition typology, and relates these to plausible assumptions regarding the relative articulatory cost of particular gestures, or their cost in particular contexts and conditions. To review:
Lenition patterns receive a unified treatment in terms of conflict between effort minimization on the one hand, and auditorily based faithfulness and fortition constraints on the other. This is formalized as a series of effort thresholds (LAZY x »LAZY x-1» etc.), interleaved with constraints on faithfulness to auditory features, and fortition constraints (presumably perceptually based), in an Optimality Theoretic constraint hierarchy.
The non-stridency of synchronically spirantized stops falls out from consideration of the isometric tension required to produce the precise partial constriction needed for strident friction.
The resistance of geminate stops to lenition likewise falls out from the isometric tension required to make a partial constriction for extended duration, and from the greater effort required to sustain voicing in geminate obstruents.
The primacy of lenition in intervocalic and similar environments follows from the greater displacement, hence effort, required to achieve some constriction target when flanked by high sonority segments.
The greater propensity for lenition in fast speech follows from the greater acceleration required to achieve a constriction target in a shorter amount of time.
The greater propensity for lenition in casual speech is captured by augmenting the base effort cost of gestures in lower registers of speech. By globally lowering the ranking of faithfulness and fortition constraints relative to effort thresholds (by boosting effort cost), gestures cross higher effort thresholds, hence more lenition occurs.
Finally, this approach was exemplified in more comprehensive analyses of lenition patterns in Tumpisa Shoshone and Florentine Italian.
