Thank you for all the very sensible and reasoned advice.
For the more excitable ones among you, no, I have no idea about which area of the law, which partner, which client, nothing at all - the intern is extremely tight-lipped about this as he of course should be.
He literally wanted to find the best English word for "amicale" and I was not sure that "friendly" would work in the context. He gave not an iota more of the context than what I have shared on here, therefore no breach of confidentiality. People in a position to know (RiversideAnne et al) have calmly pointed out that the situation I have described is a frequent practice in law firms.
I don't think it should come as a shock that an unnamed lawyer in an unnamed firm is not an expert in an unnamed field of the law. This kind of information, so anonymous, removed and everyday, is not going to harm anyone's reputation.
To answer another point, I don't think the intern is struggling, he's just keen to make a good impression. Of course his work will be carefully checked, but, as a young and keen intern, he wants to produce the best work he can, and asked me to translate "amicale"... because the fewer changes the partner makes to his work, the better the intern will feel.
And yes, a lot of this situation is about keeping the intern busy!
I really appreciate everyone's advice and have found many of the comments interesting.