Lately, I've been having a lot of near-lucid dreams.

I'll be doing something in my dream that is clearly impossible, such as speaking fluent Japanese, and I'll think, "Of course I can do this! I'm dreaming, duh!"

But the dream never becomes lucid, or in-control. I know I'm dreaming, am fully 100 percent sure, but I'm unable to take the scene into my control.

Does anyone know how to prevent this?