La diphtongaison dans les langues bantu B70-80 (Bandundu, RDC): typologie et classification historique

This article studies diphthongization or vowel breaking in some Bantu languages. Diphthongization is a well-known phenomenon in the languages of the world but occurs only rarely in Bantu languages. Nevertheless, it is well attested in the Bantu languages of groups B70 and B80 spoken in the south west of the DR Congo, in the Kwilu district. The article describes the different conditions and realizations of diphthongization in these languages. Some vowels are much more prone to diphthongization than others. Different diphthongs are classified following the original opening of the diphthongized vowel: diphthongization of mid open vowels (*e, *o), diphthongization of mid closed vowels (*ɩ, *ʊ) and diphthongization of the open and central vowel (*a). In each case, diphthongization leads to the formation of a glide preceding the broken vowel. Most instances of diphthongization can be attributed to vowel length