"Which dog is yours?"
Translation:Hangi köpek sizin?
I'd say that's about right, but I think this example makes it more clear. Suppose you're with someone in front of a bunch of dogs: Köpeklerin hangisi senin? = "which of the dogs is yours?" In English, we'd just say "Which is yours?" and the Turks would do the same: "Hangisi senin?" "Köpeklerin en güclüsü hangisidir?" -- which of the dogs is the strongest? You're correct that to say "which dog is yours?" = Hangi köpek senin?
They say here
For example, imagine that you are surprised while asking the question “Where did you buy the present?” You might exclaim, “You bought the present WHERE?!” Turkish maintains this position in sentences.
But in this case Hangi always goes first and "Köpek sizin hangi?" is incorrect.
The Turkish tree definitely neads a revision.