This study compares the use of native nominal affixes (-ness, -ship, -hood) with borrowed, potential affixes (-cion, -ance, -ity, -age, -ment) throughout the English portions of the multilingual (French, Latin, English) records of the London Goldsmiths and Grocers of the early fifteenth century. Attempting to locate evidence of the naturalization of these forms--the process by which these endings become derivational morphemes in the general English lexicon--the paper develops the notion of local productivity. This measure combines both quantitative and qualitative data to show that, even in smaller corpora, historical linguists can find evidence of the morphological status of different potential affixes for communities within particular historical moments.