This volume offers a panorama of current research into multiple varieties of Spanish from several different regions (Mexico, Puerto Rico, Spain, Costa Rica, Argentina, Bolivia, Peru, Honduras), Catalan, Brazilian Portuguese, as well as varieties in contact with English and Purépecha. The first part of the volume focuses on the structural aspects and use of these languages in the areas of syntax, semantics, sociolinguistics, diachrony, phonetics, phonology and morphology. The second part discusses the effect of interacting multiple grammars, namely, first language acquisition, second language acquisition, varieties in contact, and bilingualism. As a whole, the contributions in this volume provide a methodological balance between qualitative and quantitative approaches to Language and, in this way, represent contemporary trends in Hispanic and Lusophone linguistics.