I want to translate Turkish sentences through Google Translate for the purpose of using it in a work. Is this subject to copyright?
The "creativity" that goes into a Google translation is the program itself, which is protected by copyright. GT just provides an automated mapping from one language to another, and is legally equivalent to printing a Word document (the printed copy doesn't gain its own copyright).
The original that you feed in might be protected, however. If so, so is the translation.