While not enough is known about most medieval polyglots with regard to the ways in which they acquired languages in addition to their mother tongue, there exist untapped sources for the later Middle Ages about people who were bi- or multi-lingual. One such source is presented here containing information about the distribution of a knowledge of Latin among lay people in Poland in the year 1339. Although the sample available from the source analysed here is rather small, by placing the people who knew Latin in the context of their equals who did not, the emerging pattern indicates trends which are not unexpected. Knowledge of Latin increased both with higher social status and with urbanisation. Quite apart from these specific trends, the general picture shows a considerable knowledge of Latin among the Polish laity in the 14th century. Comparison with a similar analysis carried out for 14-century England confirms some of these findings, though a different socio-linguistic background there manifests itself in differences in the detailed pattern.