Willem Leo Marie (Leo) Wetzels (born 9 September 1951, Schinnen) is a full professor at the Vrije Universiteit Amsterdam in the Netherlands and Directeur de recherche at Laboratoire de Phonétique et Phonologie (LPP), CNRS/Sorbonne-Nouvelle in Paris. He is Editor-in-Chief of Probus International, the Journal of Latin and Romance Linguistics.
Wetzels has received numerous research grants, most recently a VU University research grant for an AIO-project on Aymara Morphophonology and the NWO internationalization grant which aims at constructing an international cooperation network in the area of Amerindian languages and cultures involving the chair of Amazonian Languages at the VU, the Centre d'Etudes des Langues Indigènes d'Amérique, CNRS, Paris, the Leiden Centre for Amerindian Studies, the Anthropology department of the Universidade Federal do Amazonas, Manaus, Brazil, and the Instituto Nacional de Pesquisas da Amazônia (National Institute for Amazonian Studies), Manaus, Brazil.
Wetzels is involved in a variety of research projects, most prominent is the one which regards nasal harmony systems. The project aims at establishing the phonological and morphological parameters that are crosslinguistically involved in long-distance nasal spreading. As part of the project, a digital database (NASDAT) was developed by Rob Goedemans (Leiden University) George N. Clements (CNRS, Paris), and Leo Wetzels himself. The NASDAT database will be made accessible to the international linguistic community via its website.
In another of his projects, Leo Wetzels and Sérgio Meira (Leiden University) present a comprehensive survey and theoretical discussion of the word-prosodic systems of the indigenous languages of South America. The study will be published as a chapter of Rob Goedemans (Leiden University) and Harry van der Hulst (University of Connecticut) to appear, Stress Systems in the Languages of the World. Berlin, Mouton de Gruyter.