I asked if she knew French.(I asked if she knows French)

Question

I asked if she knew French. vs. I asked if she knows French.

If you are a native English speaker, which sentence would you say? Or is there any difference between them?

Answer 1

I would always say knew, and would regard knows as a little odd here.

Answer 2

Both can be used. The second one slightly implies that she is someone "present" in your life, but the nuance can be ignored.

Answer 3

Both the cited examples are syntactically fine, but usually, native speakers "backshift" the verb in the complement (knew) to match the main verb (asked).

Whether backshifted or not, the meaning remains the same. It was suggested in this later question (by a non-native Anglophone TEFL teacher) that if the complement explicitly includes now...

If I knew where she lived/lives now, I'd go and see her

...then lives would have to be Present tense. But although I can understand why a non-native speaker might think that, actual native speakers don't. It's irrelevant whether or not now is explicitly included (it's always implicit in such contexts, anyway).