Bijago is highly divergent. Sapir (1971) classified it as an isolate within West Atlantic. However, Segerer (2010) showed that this is primarily due to unrecognized sound changes, and that Bijago is in fact close to the Bak languages. For example, the following cognates in Bijago and
Joola Kasa (one of the Jola languages) are completely regular, but had not previously been identified: Segerer reconstructs the ancestral forms as *bu-gof and *di-gɛs, respectively, with the following developments: • *bu-gof • > *bu-kof > *bu-kow >
fu-kow • > *bu-ŋof > *bu-ŋo >
(u-)bu • *di-gɛs • > *di-kis > *di-kil >
ji-cil • > *ne-ŋɛs > *ne-ŋɛ >
nɛ ==Comparative vocabulary==