In Journey to the Centre of the TARDIS, Clara learnt the Doctor's name from the Time War Book - but thanks to the time reset she forgot it.
Then along came The Name of the Doctor, in which Clara starts remembering those un-happened events, including the Doctor's amazement at her multiple incarnations. It is therefore likely she might also have remembered knowing his name - yet, when threatened by the Great Intelligence, it was River who said the Doctor's name - probably since Clara was busy being afraid of dying...
Nonetheless, at this point Clara definitely knew the Doctor's name (be it re-remembered or heard by River), and even though she was probably quite shaken up by traveling in his time stream, some of her conversations with Twelve (though I'm afraid I currently fail at finding one) suggest she still knows quite a lot of those re-remembered things. So, finally my question:
In The Time of the Doctor, why didn't Clara simply answer The Question instead of giving her rather lengthy (though noble) speech about the Doctor?
Was it to convince the Galifreyans to grant the Doctor more regenerations instead of returning from their pocket universe? Or did she truly not remember his name?