Original sentence: The Iranian peoples (See for local names) are a collection of ethnic groups living chiefly in vast area stretching from the Hindu Kush to central Anatolia and from Central Asia to the Persian Gulf - a region that is sometimes termed Greater Iran
Edited sentence: The Iranian peoples (See for local names) are a collection of ethnic groups usually defined by their usage of Iranian languages who live in a vast area stretching from the Hindu Kush to central Anatolia and from Central Asia to the Persian Gulf - a region that is sometimes termed Greater Iran