The topic of this dissertation is Guca, a dialect of Kwak' wala, an endangered Wakashan language that is spoken on the northern end of Vancouver Island, British Columbia and the adjacent mainland. This study is based on a corpus of elicited and naturalistic language recordings made in the home of the Wallas family of Quatsino between 2011 and 2014. The study contributes to the documentation of this little-studied dialect by describing, in Chapter 2, the phoneme inventory and the phonetic character of the segments as well as common phonological processes in this variety of the language. In addition, the phonotactics of the language are documented and investigated with regards to their potential phonetic bases in Chapter 3. The typologically unusual lexical stress system displays a "default-to-right" pattern, whereby the leftmost heavy syllable in the word is stressed, but if none are heavy, the rightmost is stressed.

The weight distinctions employed by the language shed light on our understanding of sonority and are interesting because while resonants increase a syllable's sonority and weight, glottalization of a coda consonant reduces a syllable's sonority and weight. The investigation of the acoustics of stress and of syllable weight in Guca indicate that glottalization reduces the duration and pitch of vowels followed by glottal coda consonants, and that these parameters correlate with syllable weight in this language. Chapter 4 investigates the current status and use of the lexical suffixes, an important morphophonological and grammatical structure in Guca. Semantically, these derivational suffixes often resemble roots, and they induce phonetic changes on the stems they attach to, which are not part of the regular phonological processes of the language.

Because of their structural dissimilarity to grammatical structures in the dominant English language, they are perhaps prone to early loss in the context of language endangerment. However, this study finds that they are still robustly in use by speakers and that they do not show signs of phonological weakening. The language is used primarily as a family code, but is also in use for cultural action and traditions, especially by the youngest speaker. This study contributes to the phonetic, phonological, morphological, and contextual understanding of a highly endangered dialect.