Arabic is usually classified as a Central Semitic language, and linguists widely agree that the language first emerged in the 1st to 4th centuries CE. It is now the lingua franca of the Arab world. It is named after the Arabs, a term initially used to describe peoples living in the area bounded by Mesopotamia in the east and the Anti-Lebanon mountains in the west, in northwestern Arabia, and in the Sinai Peninsula. Arabic is classified as a macrolanguage comprising 30 modern varieties, including its standard form, Modern Standard Arabic, which is derived from Classical Arabic.
As the modern written language, Modern Standard Arabic is widely taught in schools and universities, and is used to varying degrees in workplaces, government, and the media. The two formal varieties are grouped together as Literary Arabic, which is the official language of 26 states, and the liturgical language of the religion of Islam, since the Quran and Hadith were written in Arabic. Modern Standard Arabic largely follows the grammatical standards of Classical Arabic, and uses much of the same vocabulary. However, it has discarded some grammatical constructions and vocabulary that no longer have any counterpart in the spoken varieties, and has adopted certain new constructions and vocabulary from the spoken varieties.
Classical Arabic is the liturgical language of 1.8 billion Muslims, and Modern Standard Arabic is one of six official languages of the United Nations. All varieties of Arabic combined are spoken by perhaps as many as 422 million speakers (native and non-native) in the Arab world, making it the fifth most spoken language in the world. Arabic is written with the Arabic alphabet, which is an abjad script and is written from right to left, although the spoken varieties are sometimes written in ASCII Latin from left to right with no standardized orthography.
All the World Languages in One Visualization: A World of Languages.