Long-term contact with English has led to the presence in Guernésiais of a considerable number of lone English-origin lexical items (Jones, 2015). Although the presence of such items was being noted as far back as the nineteenth century, this is the first study to analyse and document them systematically. Using extensive original data, it examines these lexical items in relation to each part of speech and discusses their use in Guernésiais in the broader context of language contact. The study also considers whether, and how, lone English-origin lexical items become assimilated phonologically and morphosyntactically and whether frequency and motivation have a bearing on their usage.