Southern Uzbek, also known as Afghan Uzbek, is the southern variant of the Uzbek language and an official language of Afghanistan where it is based and has up to 6 million speakers. It uses the Perso-Arabic writing system in contrast to the language variant of Uzbekistan. Southern Uzbek is intelligible with the Northern Uzbek spoken in Uzbekistan to a certain degree. However it has differences in grammar and also many more loan words from Afghan Persian (in which many Southern Uzbek speakers are proficient).