Yes, I have read about plans for a second version of the Turkish tree.

I don't know what the timeline for this is, though.

Once you've finished the Turkish tree, you could try doing the reverse one (learning English for people who speak Turkish)! It's pretty tough, I think, and gives you a much wider vocabulary.

I don't know, but just when I did not expect them to add to any course, there were additions made to the French course, so I would not say they won't.

I would really love to have the immersion module added. It would really help me out learning, and plus, isn't that how duolingo makes their money? somehow? It seem an awesome win-win to me.

However, last I heard (on one of the threads a long while back), there was no plans to add the immersion feature. I'm pretty disappointed :(