I know how to say for instance "I was too tired to talk", I´m hoping *one* more or less correct translation of this is "Konuşamıyacak kadar yorgundum".

But what if you want to say the approximate equivalent of "My leg hurt so much I couldn´t speak"? Can this be done using "-acak kadar", or do you have to use some other way? I just want the standard way of saying such a thing so the most normal locution suits me fine. My question crops up because the subordinate clause ("Konuşamıyacak kadar") is subjectless.

/Fredrik, Stockholm

"Bacağım o kadar (çok) acıyordu ki konuşamadım" could be a good translation.

"Konuşamayacak kadar bacağım acıyordu." isn´t gramatically wrong but sounds a little weird to me. As if "-acak kadar" needs a stronger relation between cause and effect which leg hurting & not being able to speak do not seem to have. I think we need more opinions here.

I agree with Yersu. His translation sounds very good to me too.

I think the reason why "Konusamayacak kadar bacagim agriyordu" sounds wrong is that the subjects of the two verbs are not the same. The one that cannot speak is I, and the one that hurts is my leg.

Forexample if we change the verb:

Bacagim yerinden cikacak kadar agriyordu. My leg hurt as much as it would get out of its place.

Then it sounds perfect because both of the verbs belong to the same subject.

So, the condition for the use of this sentence structure should be "two verbs having the same subject"

I´m sorry for not being able to use turkish characters.

This is what I thought to be true - that if there is a subject within the subclause different from the one in the superclause, one needs to use another locution. Thank you, you are an invaluable help to me. This is the stuff that is not mentioned in grammar books.