Arabic is the official language in 26 states. Look at the map below and name the countries you see. You will discover that Arabic is spoken by almost 422 million speakers (native and non-native) in the Arab world.
Arabic is also the liturgical language of 1.8 billion Muslims and one of six official languages of the United Nations.
It is written with the Arabic alphabet from right to left and it comes in various dialects depending on a region or a country.
Arabic has influenced many other languages as well as has borrowed from other languages.
Read about the varieties - dialects of Arabic.
When learning Arabic you must bear in mind that there is:
Modern standard Arabic as well as many varieties of Arabic so called dialects.
Arabic is a Semitic language within the Afroasiatic family that originated on the Arabian Peninsula and it is classified as a macrolanguage comprising 30 modern varieties, including its standard form.
The largest differences between the classical/standard and the colloquial Arabic are the loss of grammatical features, a different word order as well as pronunciation.
Modern Standard Arabic (MSA) is also called fusḥa – فصحى
Colloquial Arabic is called ameeya – عامية
People often use a mixture of both colloquial and formal Arabic.