Old South Arabian (or Ṣayhadic or Yemenite) is a group of four closely related extinct languages. They were spoken in the far southern part of the Arabian Peninsula. They were written in the Ancient South Arabian script.
There were several Old South Arabian languages (e.g. Awsānian), of which very little evidence has survived, however. A pair of possible surviving Sayhadic languages is attested in the Razihi language and Faifi language spoken in far north-west of Yemen. Although these varieties of speech have both Arabic and Sayhadic features. It is hard to classify them as either Arabic dialects with a Sayhadic substratum, or Sayhadic languages that have been restructured under pressure of Arabic.