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).
Old South Arabian
Old South Arabian (or Ṣayhadic or Yemenite) is a group of four closely related extinct languages spoken in the far southern portion of the Arabian Peninsula. There were a number of other Old South Arabian languages (e.g. Awsānian), of which very little evidence has survived, however. A sole surviving Sayhadic language is attested in Jabal Rāziḥ in far north-west of Yemen, though the varieties of speech in neighboring areas have both Arabic and Sayhadic features, and it is difficult to classify them as either Arabic dialects with a Sayhadic substratum, or Sayhadic languages that have been restructured under pressure of Arabic.