People who really want to communicate with each other will find a way.
I think English<>French is a language pair you could get instant translations with the help of Google. So there's a tech solution that will cause humorous misunderstands but will make do. You could hire somebody who is bilingual for the first meeting to let the parents talk behind their kids' backs.
If they are French, they may actually be able to have a simple conversation in English but the boyfriend wouldn't know because they lose this ability the moment they cross the border back into France. That's a silly stereotype but I like it.
Because we don't want an American system where 16 blorbs equal 1 waboom. We want as much centi and milli as possible! Resistance is futile.