"Are you ever going to learn Czech?"

Translation: Naučíte se někdy česky?

[alturing]

Would "čestinu" be wrong here?

[VladaFu]

I don't think so. Old-style can even be "češtině".

[venik212]

Does: "Naučiye se česky někdy" sound unnatural? It was rejected.

[VladaFu]

it does