Whilst continuing our early forays into the Teda, Daza and Kanuri languages, we randomly wondered if Agisymba was perhaps a reference to the Ngizim. Lange and others have mentioned this, although Murray Last made the point more explicit through reference to the Teda and Daza languages. If the Garamantes referred to the distant land of Agisymba by a name heard from people speaking an early form of the Teda language (possible due to the Tibetsi region likely being in contact with the Garamantes in some form), it is plausible for the Ngizim to have been the ethnonym in question. Basically, the addition of -ba at the end of word would have meant "people of" (as in the -bu in Kanembu, although modern Kanuri seems to use -wu). So Agisymba would have meant A (perhaps the -ng initial sound was difficult to render in the Berber and Greek languages) + ngisym + -ba.
This theory, of course, assumes the continuity of the "Ngizim" name for 2000 years, so it is highly speculative. To our knowledge, the earliest written source referring to the Ngizim dates to the 16th century. When a French source mentions them at the end of the 17th, they were referred to as "Enghzeum." If oral traditions east of Lake Chad and clan affiliations are anything to go by, the Nguedjem (or Ngizim) were also once living in what is today Chad, in Kanem (and as part of the Bulala sultanate in Fitri, perhaps contributing to Carbou's confusion about their origins). While some ethnonyms in the Lake Chad region have persisted for several centuries (Kuri, for instance, or Bade), Ngizim would have to had survived as a name for over a thousand years before its attestation in the 1500s and 1600s.
Naturally, one would also have to account for Ptolemy's description of Agisymba seeming to imply it was near mountains. Was this meant to refer to an area closer to Air? Tibetsi? Assuming the Garamantes would have traveled south through Kawar and reached the Lake Chad area, the land of Agisymba with rhinoceroses and mountains (nearby?) had to have been to the east or west without necessarily traveling too far. The Air massif to the west is an intriguing idea, but presumably the ancestors of the Teda and Daza may have known the region in or near Kanem more intimately if they approached it from the Tibetsi and Borku regions. Again, if one assumes the Garamantes were in contact with peoples who spoke a language like that of the Teda and Daza since the days of Herodotus, and the latter groups likely knew of Kanem or Lake Chad, it is possible the presumably Berber-speaking Garamantes adopted words for southern peoples acquired through them.
Ultimately, the Agisymba as Ngizim remains just a theory. For it to be true requires one to make a number of unproven assumptions that the current data do not fully support. We assume that ancient peoples who spoke an early form of the Teda, Daza, and Kanuri languages in the central Sahara or Tibetsi were referring to a group as something like Ngizim nearly 2000 years ago. Then, through their contacts with the Garamantes, the latter referred to the Ngizim in a way that was later recorded in ancient sources as Agisymba. If the Ngizim and Bade (Bedde) were perhaps both living near Lake Chad in antiquity, then the name Agisymba could be a deformation of something like Ngizimba, referring to a region near Lake Chad, probably Kanem. One must also assume the Ngijem in Kanem are related to the Ngizim west of the lake, even though traditions in the late 1800s and early colonial period connected them to the Bulala.
