Is your girlfriend using a lawyer here? (as in the UK)
You can use the translation sites but be careful as I know of (not persoanlly) someone who did this and it wasn't accepted.However I'm not sure why.
She needs to be guided by a lawyer who deals in International law - although usually a lawyer here will appoint a power of attorney in Turkey.
Does her husband want a divorce? This will make a big difference.
Has she looked at the Turkish Consultant's website.
OK I've just spoken to Nannyjill who says that if the marriage was registered here in the UK the document she received has a translation in english on the back. If he does't have that certificate are you talking about the
Aile Cuzdani (think that's the correct spelling) It's a red book given instead of a marriage certificate. Not all of it needs to be translate and some of the pages apparently have words in more than language.
If it is this book there is only the last page written in Turkish anyway - well so she thinks.
Who has told her she needs it to be translated?
Be wary as some lawyers will charge a fortune