My primary interests are descriptive and documentary fieldwork, historical/functional/typological syntax, and historical/functional phonology.

I have been working in South America with languages of the Cariban family since 1988, when I began fieldwork on Panare in Venezuela. In all, I have worked with speakers of 15 Cariban languages, collecting comparative wordlists and morphosyntactic information for all 15, working (off and on) towards descriptive grammars of three (Katxuyana, Akawaio, and †Tamanaku), and serving as dissertation advisor for four students working with Cariban speech communities: Meira’s 1999 reference grammar of Tiriyó, Fox’s 2003 sociolinguistic/anthropological study of Akawaio, Tavares’ 2005 reference grammar of Wayana, and Yamada’s 2010 thesis on collaborative language documentation and revitalization in the Aretyry Kari’nja (a.k.a. Carib of Suriname).  I have also served as an outside member on the dissertation committee for Souza Cruz’s 2005 reference grammar of Ingarikó (Free University of Amsterdam), and I am working with Natalia Cáceres (Université Lumière, Lyon 2) as she writes her descriptive thesis on Ye’kwana.

Outside the Cariban family, I have worked briefly on Rama (Chibchan), Kiché (Mayan), Lhasa Tibetan and Kurtoep (Tibeto-Burman), and I have served as dissertation director for Guirardello's 1999 reference grammar of Trumai (isolate), Fleck’s 2003 reference grammar of Matses (Panoan), Oliveira’s 2005 grammar sketch of Apinajé (Jê), and Vallejos’ 2010 reference grammar of Kokama-Kokamilla (possible Tupían creole).

My historical and comparative work is primarily in the Cariban family, with brief forays into the Tupí-Guaraní and Jê families.

My current obsessions are serving as General Editor for Typological Studies in Language and working on two collaborative projects: Referential Hierarchies in Morphosyntax and Comparative Cariban lexicon and morphosyntax.  I continue to be fascinated by the diachronic typology of main clause ergativity—i.e., the origins and evolutionary pathways by which ergative main clause grammar is created.