Haitian has optional regressive nasal assimilation in a vowel-nasal (VN) context: /fami/ [fãmi] ‘family’. It is found also in recent loan-words in contexts where the source lacks phonetic nasalization. This process systematically underapplies in VNs that correspond to vowel-rhotic-nasal (VRN) sequences in French: [ʃãm] chambre ‘room’ vs. [ʃam] cha r me ‘charm’. We claim that etymological VRN and VR# have a different synchronic description: VRNs have no R, but VR#s do. VRNs crucially contain an empty CV that disrupts the locality between the trigger/target of nasal assimilation, hence the counterfeeding: /ʃam/ [ʃãm] ‘room’ vs. /ʃa CV m/ = [ʃam] / *[ʃãm] ‘charm’. According to this analysis, only VR#s have synchronic R: [tε ‘land’ vs. [ã-te R ¸-e] ‘to land’. VR# forms interact with the morphology in interesting ways. Haitian has a case of nonoptimizing phonologically conditioned allomorph selection (PCA), /-a/ after V and /-la/ after C: [lapli-a] ‘the rain’ vs. [ʃat-la] ‘the cat’. However, here VR# forms create opaque and nonoptimizing R-less forms: [tε-a] / *[tε- R a] ‘the land’ (cf. [ã-te R -e] ‘to land’). This is solved with underlying floating consonants and a prevocalic phonological condition on R. PCA selection is eliminated since the surface variants are generated phonologically from unique underlying forms.

This article examines the internal structure of triconsonantal roots in Tashlhiyt Berber. It is proposed that these roots have a binary-branching head-complement structure, built upon the sonorant and the segment immediately to its left. Evidence for this structure is provided by the imperfective formation. It is argued that only roots that display such a structure undergo gemination in the imperfective. This permits an account for a number of forms that are traditionally ascribed to lexical idiosyncrasy, including verbs that are made up entirely of obstruents and those whose only sonorant is in initial position.