At the Dolmabahce Palace in Istanbul i was buying an entrance ticket, and i saw a message that turkish inhabitants had 50% discount.

What would be the right way of saying: Is this discount also valid for turkish speaking people

I thought of something like:

Şu indirim türkçe konuşanlar için de geçerli mi?

Is this correct, and if not, could anyone give the proper translation?

By the way: when is  geçerli mostly used?

 Great try.. just a small correction:

Bu indirim Turkçe konuşanlar için geçerli mi?

Whenever you use valid, you use geçerli.. for your info: validity - geçerlilik

I missed a word:

Bu indirim Turkçe konuşanlar için de geçerli mi?

Thanks for your help. I´ll try it next time i´m in Istanbul