Abstract This chapter describes the languages, literacies, and identities across the variegated landscapes and communities of Britannia, using evidence and perspectives from multiple disciplines—primarily archaeological, historical, (socio)linguistic, and epigraphic. It begins with the advent of Latin and literacy, indicating in which Iron Age contexts these emerged, highlighting trade, immigration, diplomacy, and status as driving factors. Section 10.3 tackles the nature of Latinization, demonstrating regionality, and arguing that urban/rural divides are too simplistic. The story of regionality is continued through an exploration of the myriad Latins across time, place, and social groupings. Bilingualism was a factor in the creation of regional varieties, and the traces of its existence are discussed. Given that British Celtic still appears to have been widely spoken in some contexts at the end of Roman rule, consideration is finally given to the strikingly few possible examples of its written expression in the imperial period.