Dictionaries and related language reference works constitute a rich but under-exploited resource for the history of languages and of language study in the Middle Ages. Unfortunately, the size and complexity of typical medieval dictionaries make editions and analyses by traditional methods prohibitively expensive in time and money. Using as an example the Latin-Middle English dictionaryMedulla grammatice, the paper describes some central problems in the study of medieval English lexicography and the solutions provided by computers, which, with their immense speed, profound memory, and perfect accuracy can help scholars analyze, edit, and promulgate medieval documents and the linguistic data they contain.