The Chickasaw are of the Muskogean linguistic family and are one of the Five Civilized Tribes. Their native written language is nearly the same as that of the Choctaw Nation; their speech is also very similar, though dialectical differences are common. At one time, the Chickasaw language served as the medium of commercial and tribal intercourse for all the tribes along the lower Mississippi River, which was virtually controlled by the powerful and warlike Chickasaw Nation during the 17th and 18th centuries.