This dissertation argues that an undocumented member of the Defoid language family known as Àhàn should be considered a language in its own right and not a dialect of some other Yoruboid language. This conclusion is based on a comparison of several syntactic categories in Àhàn to those of standard Yoruba. An investigation of the nominal system and functional categories such as markers of tense, aspect, focus, negation and relativization are language internal evidences that support the claims of this thesis. The dissertation has both descriptive and theoretical ambitions. The descriptive part of the dissertation provides basic outline of the grammar of the language and also provides an outline of the various syntactic phenomenon that are language specific to Àhàn. The theoretical side of the dissertation examines aspect of the syntax of the language under the latest theory of generative syntax called the Minimalist Program. The applicability of Àhàn data to the claims of Minimalist syntax (Chomsky 1995, 2001 and Kayne 1994) and the modifications of the theory where necessary are part of the theoretical endeavor of this dissertation. Using the principles of microcomparative syntax (Richard Kayne 1989, 2000 2012), the thesis demonstrate how structural comparison of aspects of the syntax of Àhàn and Yoruba explicate linguistic variation, and how differences that exist between closely related languages provide data for our understanding of the properties of Universal Grammar (Collins 2013). / acase@tulane.edu