In a work that appeared in 1967 but which has lost none of its interest today, P. Alexandre gave a list of the 51 languages of Black Africa (or homogeneous dialectical and linguistic groups) that approached or surpassed a million speakers. For each of them he evaluated available documentation, on a scale of from 1 to 6. He gave the rating 1 to languages for which the documentation was poor (outdated grammars and dictionaries, incomplete or absurd systems of unscientific transcription) and the rating 6 to languages for which works conforming to modern requirements were available (correctly noted sound systems, phonological and phonetic descriptions, annotated texts, dictionaries, stylistic and dialectological studies, audio material). Only three languages merited the rating 6 and only four were rated 5. This means that only seven languages out of about 1200 could be considered as accurately described, that is, offering all the necessary guarantees to the specialist.