Amphichronic explanation and the life cycle of phonological processes

In amphichronic phonology, synchronic and diachronic explanation feed each other. Notably, the modular architecture of grammar predicts the possible modes of implementation of phonological change, including neogrammarian regularity, and lays down the track for the life cycle of sound patterns. In turn, an understanding of this life cycle relieves grammatical theory of the need to explain a wide range of synchronic phenomena. In the course of the life cycle, for example, it is normal for innovative phonological rules not to replace the phonetic processes from which they emerge, but to coexist with them. This type of rule scattering can create the appearance of morphologically sensitive phonetics without actually violating modularity. Similarly, the life cycle creates a tendency for older phonological processes to apply at higher levels in the grammar than younger ones. For this reason, younger generalized versions of existing phonological processes tend to apply in wider morphosyntatic domains, as do relatively new and aggressive processes of reduction in diachronic lenition trajectories.