Kilwa was a Swahili City State, not the origin of Swahili wee makende. Lamu was part of Zanzibar Sultanate, but Zanzibar was not the origin of Swahili. Swahili started in Lamu then spread to the rest of East African coast. Swahili City States such as Gedi, Kilwa, Zanzibar etc developed along the cost with Swahili culture. Zanzibar Sultanate was the last and the biggest of them all. That does not erase the fact that Swahili started in Lamu. Remember Lamu is older than Zanzibar and Swahili language is older than Lamu town.