But if there are two verbs (ok, with the same stem) and their action in the sentence is different, I think they are two and not one. I think your last example tells something about English ergativity rather than Turkish. In English there is stop and stop but in the Turkish variants syntactic governance is carefully marked in the verbs.

Yes. A verb cannot be both transitive and intransitve in Turkish. So some sort of modification has to be applied to get the other one from one of them.

Araba durmalı = Car must stop

That gives the following meaning:

Arabayı durdurmalısın = you must stop the car

transitive <-> intransitive

object <-> subject

Don´t you think there is correspondence here?

I understand what you mean. The usual way to play with the grammatical roles of NP´s is with passive, causative and reflexive marking. Ergative use of verbs is one of the options but not so usual in Turkish (if we want to see it in the narrow sense which I suggested). If we stick to cars

         ?Araba sürdü

would be the most impressive example of ergativity. I´m not sure if it is possible.

I recently bagged some examples of Turkish sentences which I found in texts and which in my opinion seemed ergative but I can´t find them now in my files. I´ll add them here when they kindly pop up from somewhere.

That does not sound OK but the following makes sense:

Araba güzel sürüyor = Cars drives nicely

and also

Arababın sürüşü (sürmesi) güzel = Car drives nicely (lit. Car´s driving is nice)

That´s it. When things and items begin to do things on their own that´s my idea of ergativity. But as I said my knowledge on this field is not great.

I have a feeling ergative expressions are usual in children´s talk even in languages which are not using ergative so much. For some reason I see in my eyes a small boy with his toy cars. Or a big boy to that point.

"Bu belgede ne yazıyor?" diye sorduğumuzda, Dr. Marmara belgenin en üstünde yazan cümlenin önce orijinalini okudu.

This question seems ergative to me: ´What does it write in this document?´ There is no candidate for a third person actor in the context and in normal conditions I would expect a passive voice verb.

Does it make sense to anyone?

Yes it does! Good spot!

Unutması zor.

Is it

                             - it is difficult to forget her OR

                             - it is difficult for her to forget OR

                             - is it meaningless   ?

And also can be used as an adjective

Unutması zor bir kadın = a woman hard to forget

That is what I was afraid of. This is crucial ambiguity. Does passivizing help?

                    Unutulması zor. ´It is difficult to forget her.´

Unutulması zor bir kadın = a woman hard to forget