Avoidance of Dissimilar Labial Onsets: The Case of Subanon

Early work on the statistical structure of the “Proto-Austronesian” (PAn) morph revealed a distinct pattern of avoidance between the onsets of adjacent syllables if these were nonidentical labials (*pVb, *pVm, *bVp, *bVm, *mVp, *mVb). Descriptions of many attested languages that have retained a reflex of PAn *-um- ‘actor voice’ show that this dispreference extends to affixed words, in which case the avoidance triggers a pattern of allomorphy that has been called “pseudo-nasal substitution.” While this pattern is very prominent for word bases that contain an initial labial stop and a reflex of the infix *-um-, it is much less prominent for word bases that contain an initial labial stop and a reflex of the prefix *ma- ‘stative verb’. Variations in the way this family-wide dispreference is realized in particular languages are surveyed briefly, and then it is shown that Subanon of the southern Philippines extends the usual avoidance pattern by adding to pseudo-nasal substitution a metathesis of mo- (< *ma-) so as to convert even the reflex of *ma-p or *ma-b to an innocuous medial homorganic nasal-stop sequence.