The history of the [ɨm] causatives in Mapudungun

This paper describes and analyses a historical alternation in what contemporary Mapudungun has developed as a set of transitive roots ending in [Cɨm], where C can represent a labial stop, a retroflex affricate or a velar stop. These forms are historically related to a causativisation process formed with a root ending in what is now a fricative plus the now-unproductive suffix [-ɨm]. An example of this pattern today is the adjective [laf] ‘(adj) flat’ vis-à-vis the transitive verb [lapɨm-] ‘to stretch (out)’. This paper posits that the word-internal stop consonant preceding [ɨm] is the unaffected remnant of an ancestral fricativisation process that targeted final stops in older Mapudungun. By presenting evidence from the historical record, the trajectory of these linguistic patterns is analysed in relation to the theoretical assumptions of the Life Cycle of Phonological Processes. This work contributes to theoretical questions about what is possible in language change as well as to the internal reconstruction of this language isolate.