This issue of the Journal of Historical Sociolinguistics aims to contribute to our understanding of the role of merchants in language standardisation by focussing on how merchants can be seen as agents of linguistic change across various European vernaculars at various points in time. By analysing data from a varied set of languages, including Italian, Norwegian, Spanish, and Dutch, the authors provide insight into merchant writing in relation to language standardisation from different perspectives and at different times. The extant material available from merchants, their role as intermediaries in the commercial world, their functional and variable literacy, and their social and geographical mobility, all mean that merchant writing is able to offer unique insights into the vicissitudes of language history.