Because the literacy rate was high in Muslim Africa, and because of a concentration of learned Muslims in America...the literacy rate among Muslims was in all probability higher than it was among slaveholders. Thomas Ewbank -- a founder and president of the American Ethnological Society -- who traveled in Brazil in 1845-46, dined with a Bahian planter who had this opinion about the Mina of Bahia: "Shrewd and intelligent they preserve their own language, and by that means organize clubs and mature schemes of revolution that their Pernamhuco brethern have repeatedly attempted to carry out. Some write Arabic fluently and are vastly superior to their masters." As Brazilian scholar Gilberto Freyre remarked, "in the slaves' sheds of Bahia in 1853, there were perhaps more persons who knew how to read and write than up above, in the Big Houses...."
Sylviane A. Diouf, SERVANTS OF ALLAH: African Muslims in the Americas, 15th anniversary edition, New York University Press, 2013: 160