The focus of this dissertation is nasality and nasalization in Atchan, a Potou language of the Kwa branch of Niger-Congo spoken in and around Abidjan, Côte d’Ivoire. Unlike most of the world’s languages, Atchan lacks a phonemic contrast for nasality in consonants. Nasality nonetheless plays an important role in Atchan, at multiple levels of grammar. Drawing on data collected over years of documentation work with Atchan speakers, I propose that sur- face nasality in the language is attributable to three phenomena: lexically specified nasality at the level of the syllable, articulatorily motivated carryover nasalization across syllable boundaries, and the docking of floating [+nasal] autosegmental features which express certain morphological features. Throughout, I support descriptive generalizations with evidence from articulatory measurements, including spectral information and nasal and oral airflow measurements. These findings have important implications for the typology and representation of nasal contrast: specifically, the Atchan data contributes to ongoing discussion of nasal contrast systems, supporting the view that systems which lack a contrast for nasality in consonants may be better characterized as instantiating prosodic rather than segmental nasality, in which [nasal] is a syllable-level feature that secondarily enhances a sonority contrast in consonants.
In the dissertation, I situate Atchan nasality and nasalization within the larger picture of the Potou-Tano branch of the Kwa family, drawing on a detailed survey of 30 languages spoken across Côte d’Ivoire and Ghana. In languages where consonant nasality is predictable from surrounding phonological context, nasality operates as a dimension of another consonant contrast: this contrast is sonority in Atchan, inherited from Proto-Potou-Tano. In many Tano languages, this contrast is voicing. Atchan, as one of only two Potou-Tano languages which maintains a four-way contrast between voiceless fortis (aspirated), voiceless lenis (unaspirated), voiced fortis (obstruent), and voiced lenis (sonorant) consonants, represents an important piece in the puzzle in understanding this nasal contrast system.