As far as I know, and I can remember, all popes know several languages and I am under the understanding that that's required for the position itself. So, I guess 2 questions come here.
If yes, 2) Since when has it been so? And why?
there are actually pretty much no requirements to be pope. The pope just has to be catholic and male.
e.g. 1455 Pope Callistus III was elected despite not being a priest and Urban VI was the last non cardinal.
all popes know several languages
it's more goes with the territory. the curia is the oldest western bureaucracy involving people from literally all over the globe. As you rise high in such multinational organizations it helps to know multiple languages and thus as a cardinal you probably do (there is also the question of seminary schools requiring other languages which i cannot answer). hope this helps.