Who could speak Latin in the Middle Ages?
Certainly not common folk!: it was spoken by priests (though some of them frankly badly, as we can check in the complaints by bishops in the council and synod records which have reached us) and scholars, that is to say: humanists and scientists. Alcuin from York for example, being an Englishman, could teach at the Sorbonne and many other European universities, and his pupils fully understood him, because they knew Latin. But let’s not forget that scholars were very few, and university students were very few more. The clergy had (and in some countries like Spain still have) very long studies, they study for twelve long years, which is long enough to master a difficult language. However, if you ask any expert in Classical Languages, he or she will tell you that NOBODY can SPEAK Classical Latin or Greek, and the one the priests speak is not classical, but Vulgar Latin. More than thirty years ago the British lite universities of Cambridge and Oxford taught their degrees either in Latin or
