This research study examines the pedagogical considerations and linguistic challenges regarding teaching Portuguese to speakers of Spanish. That the Portuguese language is similar to Spanish presents a unique set of advantages and challenges to students and instructors. The study of this population of students has grown considerably since the 1980s, and most notably since the 2000s. Two unique and growing populations of Portuguese learners come into focus during this study--both native and heritage Spanish speakers. Their specific learning goals are analyzed in detail, particularly regarding what types of innovative linguistic methods and assessment strategies are relevant for these learners.