There are two levels of class that we take: diction classes and language classes. In diction classes, we focus only on how to pronounce the language and sound like we speak it, but we don’t actually learn to speak it. Our language classes, by contrast, tend to be normal language classes, but with an added emphasis on conversation skills (we mostly need to speak, not write, in foreign languages).
A typical conservatory undergraduate degree will require a year of language class in French, German, and Italian. They’ll also require at least a semester of diction in those languages.
I didn’t do an opera undergrad, but I did two grad degrees, both of which came with a year of diction in each of those languages, plus a semester of diction in Russian for each graduate degree. Subsequently, I did two years in the Lindemann Program at the Metropolitan Opera, which came with independent language study, one-on-one, in German, Italian, Russian and Czech (I spoke fluent French from childhood but they would have given me that, too, if I’d asked).