There is no Bantu Alliance but there are three supra regional groups the SADC and EAC and ECCAS that make up the Bantu countries per the linguistic map I can go and provide references for all 19 predominately bantu countries and the 4 islands as well Let me know what you think is best But the three organizations removing overlap and accounting for non Bantu groups is sufficient If we have a page on Bantu peoples there should be an estimation as to their population If there is an easier way let me know