Laryngeal reduction and mora deletion in Mixtec: Phonetics in phonology

This paper describes a process of laryngeal reduction in San Martín Peras Mixtec (SMPM; ISO: jmx), an Otomanguean language spoken in Oaxaca and by diasporic communities throughout Mexico and the US. In this process, roots containing a laryngealized vowel often appear in a highly reduced form in fast speech. Laryngeal reduction is gradient, dependent on speech rate, and lacks a phonologically-defined conditioning environment, giving it the characteristics of a phonetic process. However, it is at least sometimes correlated with a phonological process of mora deletion, as evidenced by the fact that some highly reduced laryngealized roots—but no unreduced laryngealized roots—undergo a phonological tone sandhi alternation that applies only to mono-moraic rising tones. The phonological process of mora deletion is argued to be conditioned by the same phonetic factors that drive laryngeal reduction, constituting an instance of a phonological process triggered by purportedly phonetic factors.