David Dalby & Michael Mann 
Thesaurus of African Languages [PDF ebook] 
A Classified and Annotated Inventory of the Spoken Languages of Africa With an Appendix on Their Written Representation

Originally published in 1987, this thesaurus is concerned with the spoken languages of Africa. Languages are grouped into a relatively large number of sets and subsets within which the relationship of languages to one another is locally apparent and uncontroversial. The volume presents the languages in classified order with notes on each language, their variant names and immediate classification, and reference to the sources consulted. One section offers an exhaustive list of the languages spoken as home languages by local communities in each state, together with details of languages widely used for inter-group communication, given official recognition, or used in education or the media. There are brief phonological analyses of a broad sample of some 20 African languages and a comprehensive bibliography and language index to the whole work