Polyglotta Africana
Polyglotta Africana is an 1854 study by the German missionary Sigismund Wilhelm Koelle, in which the author compares 156 African languages. As a comparative study it was a major breakthrough at the time.
Koelle based his material on first hand observations, mostly with freed slaves in Freetown, Sierra Leone. He transcribed the data using a uniform phonetic script devised by the Egyptologist Karl Richard Lepsius. Koelle's transcriptions were not always accurate; for example, he persistently confused with and with. His data were consistent enough, however, to enable groupings of languages based on vocabulary resemblances. Notably, the groups which he set up correspond in a number of cases to modern groups:
