For decades, a small set of major world languages have formed the basis of the vast majority of linguistic theory. However, minoritized languages can also provide fascinating contributions to our understanding of the human language faculty. This pioneering book explores the transformative effect minoritized languages have on mainstream linguistic theory, which, with their typically unusual syntactic, morphological and phonological properties, challenge and question frameworks that were developed largely to account for more widely-studied languages. The chapters address the four main pillars of linguistic theory - syntax, semantics, phonology, and morphology - and provide plenty of case studies to show how minoritized language can disrupt assumptions, and lead to modifications of the theory itself. It is illustrated with examples from a range of languages, and is written in an engaging and accessible style, making it essential reading for both students and researchers of theoretical syntax, phonology and morphology, and language policy and politics.