Saudi Arabia
The official language of Saudi Arabia is Arabic. The three main regional variants spoken by Saudis are Hejazi Arabic (about 6 million speakers), Najdi Arabic (about 8 million speakers), and Gulf Arabic (about 0.2 million speakers). Saudi Sign Language is the principal language of the deaf community. The large expatriate communities also speak their own languages, the most numerous of which are Tagalog (700,000), Rohingya (400,000), Urdu (380,000), Egyptian Arabic (300,000), and Indonesian (250,000).
Arabic
The sociolinguistic situation of Arabic in modern times provides a prime example of the linguistic phenomenon of diglossia, which is the normal use of two separate varieties of the same language, usually in different social situations. In the case of Arabic, educated Arabs of any nationality can be assumed to speak both their school-taught Standard Arabic as well as their native, mutually unintelligible "dialects"; these dialects linguistically constitute separate languages which may have dialects of their own. When educated Arabs of different dialects engage in conversation (for example, a Moroccan speaking with a Lebanese), many speakers code-switch back and forth between the dialectal and standard varieties of the language, sometimes even within the same sentence. Arabic speakers often improve their familiarity with other dialects via music or film.