Florentine Italian, as described in Giannelli and Savoia (1979), displays extensive lenition of all its consonants. Most notably, the stops, under various phonetic and stylistic conditions, can be spirantized to fricatives or approximants, voiced, debuccalized, or dropped entirely. On the other hand, certain aspects of Florentine lenition appear to be stable across speech rates and registers, such as lenition of intervocalic affricates [tf, d3] to fricatives U,3]. Yet the stable and variable patterns are intimately bound up with one another, requiring a unified analysis. I will show that both can be analyzed in terms of conflicts between avoidance of certain levels of effort expenditure vs. lenitionblocking constraints. In particular, Florentine illustrates the following general points, anticipated in previous chapters: • Effort thresholds correspond to the observed contexts in which lenition

occurs, as well as constraining the possible outcomes of lenition. • Effort thresholds correspond to the speech rate and register conditions under

which lenition is more likely to occur. The higher the rate or the lower the register, the broader the contexts under which lenition occurs, and the more extreme the lenition which occurs in a given context.