Natural classes in cooccurrence constraints

• Phonologically supported ejective-[ʔ] and aspirate-[h] classes are underlearned.
• Natural classes are based on phonetically salient properties.
• Non-contrastive glottal stop may be phonologically inactive.

Natural classes are typically defined by some shared phonetic property, though the segments within such a class may differ substantially along other dimensions. This paper explores two such classes in Quechua: the class of [spread glottis] segments, aspirates and [h], and the class of [constricted glottis] segments, ejectives and [ʔ]. While aspirates and ejectives pattern with their glottal counterparts in the cooccurrence phonotactics of the language, nonce word tasks only find weak evidence of these natural classes. Instead, there is evidence for strong phonotactic restrictions on aspirates and ejectives to the exclusion of their glottal counterparts. It is proposed that the preference for classes of laryngeally marked stops is phonetically based, deriving from the salience of the phonetic properties unique to stops.