Why phonetically-motivated constraints do not lead to phonetic determinism: The relevance of aspiration in cueing NC sequences in Tumbuka

This paper examines the role of phonetic cues to postnasal laryngeal contrasts, language-specific differences in the use of these cues, and the phonetic naturalness of the different cues. While many studies have shown that long stop closure duration is a well-established cue to voicelessness in the postnasal context (see, e.g., Cohn & Riehl 2012, who claim this to be a universal property), the present study focusses on the role of aspiration noise in maintaining a voicing contrast in the postnasal environment. It provides experimental data from the Bantu language Tumbuka to illustrate that aspiration noise can preserve a postnasal laryngeal contrast even when stop closure duration is short. Though typologically less common, we show that the use of aspiration as a cue is also phonetically motivated. Furthermore, we show that such phonetic motivation should not be directly incorporated into phonology (e.g., as markedness constraints in OT). Instead, we employ the BiPhon model (Boersma 2007), which allows for a strict distinction between the modules of phonetics and phonology, and which formalizes the mapping of phonetic cues onto phonological representations via cue constraints, avoiding the problem of phonetic determinism.