The literary language, called Modern Standard Arabic or Literary Arabic, is the only official form of Arabic. It is used in most written documents as well as in formal spoken occasions, such as lectures and news broadcasts.
Some of the spoken varieties are mutually unintelligible, both written and orally, and the varieties as a whole constitute a sociolinguistic language. This means that on purely linguistic grounds they would likely be considered to constitute more than one language, but are commonly grouped together as a single language for political or religious reasons (see below). If considered multiple languages, it is unclear how many languages there would be, as the spoken varieties form a dialect chain with no clear boundaries. If Arabic is considered a single language, it is perhaps spoken by as many as 422 million speakers (native and non-native) in the Arab world, making it one of the six most-spoken languages in the world. If considered separate languages, the most-spoken variety would most likely be Egyptian Arabic with 89 million native speakers—still greater than any other Afroasiatic language. Arabic also is a liturgical language of 1.6 billion Muslims. It is one of six official languages of the United Nations.