Lenition is a process of weakening. The diachronic development in (i) can be analyzed as a case of lenition (Hooper (1976), Katamba (1989)):
(i) Latin Italian Spanish French vita vita vida vie 'life' t -> t -> d -> 0
Lenition can be explained by referring to the sonority hierarchy: the progression down the sonority hierarchy is from a voiceless stop to a voiced stop before deletion takes place. Lenition can also occur in one language.
- Hooper, J. 1976. Introduction to Natural Generative Phonology, Academic Press, New York.
- Katamba, F. 1989. An Introduction to Phonology, Longmans, London.