Old Persian is one of the oldest Indo-European languages. It was spoken in the ancient Persian Empire, which stretched from the Balkans to the Indus Valley. The language is related to Avestan, another ancient Iranian language. Old Persian was written in a cuneiform alphabet, which was also used for other languages, such as Elamite and Akkadian. The language died out in the 3rd century CE, but some of its words and phrases were borrowed by other languages, such as Arabic, Turkish, and Sanskrit.