In written language as well as in spoken communication, codeswitching is often accompanied by flagging. Directing attention to features which are important or potentially difficult to process, flags also appear in medieval manuscripts and may have a visual or a verbal form. Visual flagging may involve, for example, the use of red ink, underlining, or marginal manicules, while verbal flags include metalinguistic labels specifying the embedded language or the main language, and intratextual translations of other-language material. Based on data from a large number of manuscripts produced in England in the long twelfth century, this study examines both Latin code-switches in Early Middle English texts and English switches appearing in Latin manuscripts. It considers motivations for both code-switching and concomitant flagging, and outlines a tentative typology of verbal and visual flagging, which may also be applicable to other periods and language pairs.