Aún or todavia

[BobRitter]

Lo siento Chileno. Creo que ambos fraces son mas o menos iguales pero para mi el primero parece mejor.

Both of these seem to be stating completed actions up to now and the current result of the action. I did study every day until now and as of now I still can not speak Spanish.
Even though I study... Absolute confirmation that I really do study every day. BEST
Even studying every..... Very close but possibly not quite as strong confirmation.

This is quite different:
Even if I study every day I still would not be able to speak Spanish.
This is talking about the future:
Even if (starting today) I study every day I still would not be able to speak Spanish (in the future).

Hope this helps. It is very difficult. It always amazes me how complex every day speech can be be when I try to explain it.