The Auchinleck Manuscript was produced in the 1330s in London and is best known to scholars of Middle English literature on account of the romances that it transmits. Several of these texts treat the establishment and defence of England and it has been argued that their interest in English history is matched by the language in which almost all of the manuscript’s texts are written: English. This paper reconsiders the Englishness of the Auchinleck Manuscript via a quantitative analysis of its lexis. We show that a comparatively large proportion of the Auchinleck lexicon has connections to French and that, of these words with French connections, many do not appear to have been much used in English writing before the 1300s. Our statistics are derived via programme scripts that match Auchinleck lexicon items to headword entries in the Middle English Dictionary (MED) and collect data pertaining to word etymology and earliest dates of citation from those entries. Where previous studies have emphasized the porous boundaries between English and French in fourteenth-century English contexts, we posit that some poets might aim to make creative capital out of the deliberate juxtaposition of the languages. The argument is supported by a series of visualizations; interactive versions of these visualizations and the data on which they are based are archived at our project website (https://solliryc.github.io/AuchinleckDataViz/).