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).
Modern Standard Arabic
The sociolinguistic situation of Arabic in modern times provides a prime example of the linguistic phenomenon of diglossiathe use of two distinct varieties of the same language, usually in different social contexts. This diglossic situation facilitates code-switching in which a speaker switches back and forth between the two dialects of the language, sometimes even within the same sentence. People speak MSA as a third language if they speak other languages native to a country as their first language and colloquial Arabic dialects as their second language. Modern Standard Arabic is also spoken by people of Arab descent outside the Arab world when people of Arab descent speaking different dialects communicate to each other. As there is a prestige or standard dialect of vernacular Arabic, speakers of standard colloquial dialects code-switch between these particular dialects and MSA.