3littlefrogs - that is still a very strong set of results, especially if she has A*s in language GCSEs. I'm not a MFL tutor, but we do deal with them quite a lot because of the English and ML admissions process. Here's a useful bit of the MFL website which explains the criteria:
www.mod-langs.ox.ac.uk/faqs#13
(see also the section immediately above on entrance procedure)
As you can see, GCSEs play only one part in a whole set of criteria. Her AS grades, A level predictions, written work, language tests and interview performance will be the decisive factors. One rogue B at GCSE would not count her out, even in English, if the rest of her 'portfolio' met the necessary standard (and if the school felt strongly that the B was explained by particular factors, they could say that briefly in the reference). I can't make any promises, but it is all still in her hands and all to play for.
She might like to cheer herself up by starting to explore this site:
staircase12.univ.ox.ac.uk/
Essentially, there is no point making a final decision until you have the AS grades and A2 predictions. Dealing with the disappointment might be the key thing here - if she does apply in due course, she will need to accept that we turn down far more than we accept, and she may be in that majority of disappointed applicants (who were just beaten by candidates with yet more potential). But she may not, and the only way to know for certain is to apply if it seems realistic to do so.