That had nothing to do with the topic though... hopelessdreamer just wanted our opinion on the question "If you learn about lucid dreaming in English, can your subconscious still practice it in your first language?"
Anyway, hopelessdreamer, I know what you mean since my first language is Swedish and I only read about lucid dreaming in English. As for your question... I'm not sure. As HAGART said, I think your subconscious will understand what you mean no matter what language you speak because well, it's a part of you after all. But I don't think it would do any harm to translate some lucid dreaming terms into your first language and start using them.