Arabia boasted a wide variety of Semitic languages in antiquity. In the southwest, various Central Semitic languages both belonging to and outside of the Ancient South Arabian family (e.g. Southern Thamudic) were spoken. It is also believed that the ancestors of the Modern South Arabian languages (non-Central Semitic languages) were also spoken in southern Arabia at this time. To the north, in the oases of northern Hejaz, Dadanitic and Taymanitic held some prestige as inscriptional languages. In Najd and parts of western Arabia, a language known to scholars as Thamudic C is attested. In eastern Arabia, inscriptions in a script derived from ASA attest to a language known as Hasaitic. Finally, on the northwestern frontier of Arabia, various languages known to scholars as Thamudic B, Thamudic D, Safaitic, and Hismaic are attested. The last two share important isoglosses with later forms of Arabic, leading scholars to theorize that Safaitic and Hismaic are in fact early forms of Arabic and that they should be considered Old Arabic.