We review and elaborate an account of consonantal strength that is founded on the model of speech as a modulated carrier signal. The stronger the consonant, the greater the modulation. Unlike approaches based on sonority or articulatory aperture, the account offers a uniform definition of the phonetic effect lenition has on consonants: All types of lenition (such as debuccalisation, spirantisation and vocalisation) reduce the extent to which a consonant modulates the carrier. To demonstrate the quantifiability of this account, we present an analysis of Ibibio, in which we investigate the effects of lenition on the amplitude, periodicity and temporal properties of consonants. We propose a method for integrating these different acoustic dimensions within an overall measure of modulation size. Not only does the modulated-carrier account cover all the classically recognised lenition types, but it also encompasses loss of plosive release in final stops – which, although not traditionally classed as lenition, is clearly related to processes that are.

This paper provides evidence for the activity of the Obligatory Contour Principle (OCP) as a constraint on dynamic alternations in the synchronic grammar of Qatari Arabic. It shows that the OCP is subject to proximity and to a gradient similarity effect. In Qatari Arabic, there are two variable phonological alternations that interact with the OCP, affrication and lenition. The velar stops /g/ and /k/ affricate to [ʤ] and [ʧ], respectively, when adjacent to [i(:)]. However, affrication is blocked when the outcome includes a sequence of segments that are highly similar. Lenition applies variably to the phoneme /ʤ/, which surfaces as [ʤ] or [j]. Usually, the probability of lenition applying to its eligible candidates is around the level of chance. The process, however, applies categorically when a violation of the OCP would otherwise be incurred. The data are analyzed within the framework of Optimality Theory.