From a linguistic point of view, the “Zanjian” phase appears to be marked not only by a differentiation of the “Proto-Sabaki” language (spoken by Bantus settling between the Tana River and southeastern Somalia) into various groups, but also by the expansion of these groups, which D. Nurse links to trade blooming “in contact with foreign traders.” The Swahili and Comorian languages had split by the ninth century (Nurse 1983: 140; Nurse and Hinnebusch 1993: 494–495). During the period between the sixth and tenth centuries, a type of pottery which M. Horton has called Tana Tradition Ware (also referred to as Triangular Incised Ware [TIW] by F. Chami) – also found decorated with crisscross patterns or zigzag bands – replaced Early Iron Age Ware (EIW). Research to date shows that Tana Ware has been discovered from the Kenyan coast to Mozambique and in the Comoros, but not in Madagascar, except at a site on the Androy coast.