Can you speak Turkish?

Türkçe konuþuyorum?

 Türkçe konuþabilir misin?

ReyhanL is correct 

Türkçe konuþabilir misin?

Can you speak Turkish?

Note that in the above sentence ´mi´ is the question word, and when combined with the ´sin´ suffix means ´are you´

and the ´abil´ suffix means can do or able to.

Türkçe konuþuyorum.

I am speaking Turkish.

I think I´m right in saying that they don´t always use the ´can´ form of the verb but just say

´Türkçe biliyor musun?´

 It´s what I hear mostly!

 Yes, I suppose ´türkçe biliyor musun´ is more frequent than ´türkçe konuþabilir misin´. The last one sounds more like a request than a question as to whether someone speaks/knows Turkish.