Generally, no, since these language packs are downloaded from Microsoft directly. Of course, someone might have been able to hack in to MS and corrupt their language pack, but that is rather unlikely since there are already so many holes in any Windows OS that it would be easier for them to exploit these holes than try to get into MS mainframe to corrupt the language pack.
OTOH, if you mean "harm" by way of slowing your computer's performance, then yes. Afterall, these are little packets of instructions which do take up space on your harddrive, space which could be put to better use, like allocating extra dynamic memory.
Anyway, the language pack isn't much use unless you know how to read the language you're going to install. It won't translate the words into English, it just shows the original characters rather than displaying some WingDings in its place.
