Apart from terminology, this differs from Harold Fleming's earlier (1976) classification in including the Mao languages, whose affiliation had originally been controversial, and in abolishing the "Gimojan" group. There are also differences in the subclassification of Ometo, which is not given here.
The Omotic languages were formerly classified as the West subgroup of the Cushitic languages, but as more data became available, Harold Fleming proposed that they constituted a separate subgroup of Afro-Asiatic, and this has become the prevalent view. Whether the old Cushitic language family should be split in two in this way is still controversial among some linguists; others, conversely, such as Paul Newman, regard its differences from other Afro-Asiatic languages as so great as to cast doubt on its very inclusion in the phylum, and regard it as being, at closest, the phylum's most distant branch.
They should not be confused with the unrelated Omotik language, a nearly extinct Nilotic language of Tanzania with a similar name.
Notes
^ Raymond G. Gordon, Jr, ed. 2005. Ethnologue: Languages of the World. 15th edition. Dallas: Summer Institute of Linguistics.
Sources cited
Bender, M. Lionel. 2000. Comparative Morphology of the Omotic Languages. Munich: LINCOM.
Fleming, Harold. 1976. Omotic overview. In The Non-Semitic Languages of Ethiopia, ed. by M. Lionel Bender, pp. 299-323. East Lansing, MI: Michigan State University.
General Omotic bibliography
Bender, M. L. 1975. Omotic: a new Afroasiatic language family. (University Museum Series, 3.) Carbondale, IL: Southern Illinois University.
Hayward, Richard J., ed. 1990. Omotic Language Studies. London: School of Oriental and African Studies.
Hayward, Richard J. 2003. Omotic: the "empty quarter" of Afroasiatic linguistics. In Research in Afroasiatic Grammar II: selected papers from the fith conference on Afroasiatic languages, Paris 2000, ed. by Jacqueline Lecarme, pp. 241-261. Amsterdam: John Benjamins.