The language on which this short study is based is Lingala, the very interesting lingua franca spoken along the vast stretch of the central part of the main Congo River. The language is spoken almost entirely by Bantu tribes, all of whom have also their own tribal languages. Naturally there is considerable affinity between these languages, and in some senses Lingala may be said to represent the Highest Common Factor of them. Phonetically they are almost identical, and so Lingala has preserved a clearly marked phonetic system, a brief account of which should not be out of place here.