Drawing on spoken corpus data, this study traces the emergence and development of Norman French-influenced innovations in the nativised L2 variety of Jersey English and compares them to features in the speech of French-speaking learners of English. The comparison shows that such innovations do not differ from errors in a learner variety on a formal linguistic level and that they arguably result from the same processes as are present in foreign language acquisition, such as transfer or simplification. The paper therefore argues that innovations can only be identified reliably in retrospect, once they are more widely accepted in the speech community. It also points to the social factors that are crucial in shaping the use and probable fates of former innovations in Jersey English and suggests a typology of innovations according to their developments.