We report on an automated extraction and analysis of lexical items from a digitized dictionary of Hiaki (Yaqui), which enabled the discovery of patterns in the distribution of word- final vowels according to lexical category. Headwords were extracted from a Microsoft Word dictionary file with a Perl script, then binned and counted according to lexical category and word- final vowel. There were statistically significant interactions between lexical category and word- final vowel, and a near-categorical prohibition on word-final [i] in verbs and word final [e] in adjectives. The exceptions were few enough in number that we undertook detailed item-by-item investigations of each, discovering that in the case of putative ‘verbs’ ending in [i], the dictionary- makers had miscategorized, misspelled, or otherwise mistakenly presented the forms. We present a theory that active Voice has an exponent [-e] in Hiaki, which coalesces with stem-final [i] verbs to yield surface [e] word-finally in free verb forms.