The original home of the Turks was a small area in central Asia. In a relatively short time their language and culture spread a great distance. There can be no doubt that they had a great influence on many Slavic cultures, especially the southern Slavs such as the Bulgarians.

I don't see the Slavs as being very close to the Turks though...as far as linguistics go the Slavs are closer to the Iranians and this is not counting the Balts who could be considered siblings IMO. Both Slaviv and Baltic languages belong to the Satem branch of the Indo-European family aling with the Iranian and Indic languages.