MML student here (Newnham). As above - they are more similar than different.
Supervisions for the language-side of things will most likely be in your college, but this will depend on your chosen languages, and the number of people doing said languages at your college. Sometimes, they're in department but they've been organised by your college with a staff member who's linked to your college - this was the case with Spanish for me.
As for the literature (and this would apply to linguistics too), the supervisions are again, usually organised by college but as you move into second year and begin to specialise, you're much more likely to be mixed with people from other colleges in your supervisions (whereas first year the papers are all compulsory and you don't have choice in that).
The one thing I would say to consider is, at the least, MML-specific travel grants. These do vary by college, at times considerably, so if this is something you're interested in I'd do some research. As for number of supervisions, these are mostly similar across colleges.