While in Sierra Leone he also collected linguistic material from many African languages, some of it from freed slaves such as Ali Eisami, a Kanuri man. Koelle's major work, Polyglotta Africana (1854), is considered the beginning of the serious study of a large range of African languages by European scholars.
While in Sierra Leone, he collected linguistic materials from numerous African languages, some of which came from freed slaves like Ali Eisami, a Kanuri man. Koelle's major work, Polyglotta Africana (1854), is considered the beginning of serious European research on a wide range of African languages.