Postlabial raising and paradigmatic leveling in A’ingae: A diachronic study from the field

This paper discusses and analyzes the variation between ai and ɨi in A’ingae(or Cofán, an Amazonian isolate, ISO 639-3: con) by comparing the data reported in Borman’s (1976) dictionary with contemporary productions. In Borman (1976), ai does not generally appear after labial consonants; the distribution of ɨi is not restricted. In some modern productions, postlabial ai is allowed when the diphthong crosses a morpheme boundary (a + i). I propose that Borman’s (1976) distribution of ai and ɨi is a consequence of a diachronic change of ai to ɨi after labial consonants (* ai > ɨi /B _). The contemporary distribution reflects paradigm leveling and contact-induced replacement: Borman’s (1976) ɨi corresponds to contemporary ai if a is present in another related form. In novel productively-formed words, the availability of postlabial raising is speaker-specific. The proposed sound change of postlabial raising (*ai > ɨi /B _) is unusual and lacks obvious phonetic motivation. I speculate that postlabial raising reflects postlabial rounding (*ai > * ui /B _) opacified by subsequent unconditioned unrounding and centralizing of the back round vowel (* u > ɨ).