In this book we explore the construct of phonological redeployment which can be described as taking a contrastive element from your L1 grammar and using it in a new way to represent a novel contrast in an additional language. We look at learning a new liquid contrast, a new place contrast, a new vowel contrast, and show how redeployment accounts for the observed patterns. We look at learning new laryngeal features such as voicing, aspiration, and ejection. We also touch upon the field of language contact, showing how features can be redeployed within a language to set up new contrasts resulting from contact. We also review cases where learners take an L1 feature from one domain (a vocalic feature) and redeploy it to acquire a new L2 consonantal place contrast. We conclude by situating the studies within the literature on monolingual normativity to emphasize that different does not mean deficient.