#central sudanic

(1) these have vaguely Lithuanian-like "liquid diphthongs", where /CVR/ syllables pattern as akin to /CVV/ in that they can carry two tones; so /ɓaː˩˧/ (ɓàā) 'to find on the ground', /ⁿdeː˩˧/ (ndèē) 'to filter', /ãj˩˧/ (à̰ȳ) 'to flee'; but also: /dʌr˩˧/ (də̀r̄) 'firstborn child', /il˩˧/ (ìl̄) 'to be dark' /nin˧˥/ (nīń) 'corpse' (all these with about the same shape in most Sara varieties). They arise quite straightforwardly by tone cheshirization after loss of final vowels: e.g. in Kaba-Na (a non-Sara language) 'corpse' is /nu˧nu˥/ (nūnú), and e.g. Western Sara /gaŋ˥˧/ (gán̄g) 'a type of drum' corresponds to Central /ga˥ᵑgɨ˧/ (gángɨ̄), Eastern /ga˥ᵑga˥/ (gángá).

(2) consonant systems are fairly tame for the region, there are implosives /ɓ ɗ/ and prenasalized stops + affricate /ᵐb ⁿd ⁿdʒ ᵑg/, but not even labial-velar stops; however, they all have a pretty interesting vowel system /a e i ʌ ɨ ɔ o u/ ±nasalization, with two additional central vowel qualities and an open-mid rounded vowel (more stable than /o/ which varies often with /ʌ/ or /u/; maybe I should call the former of these /ɘ/ instead). Not a lot of evidence of ±ATR pairing amongst these either. Geographically closest relatives have the rather more Sahel-looking /a ɛ e i ɔ o u/. No idea so far how this arises, it kind of seems that most vowels can centralize (*i *u > *ɨ, *a *e *o > *ʌ?), but conditioning seems iffy, and maybe this is backwards and central vowels rather go back to Proto-Sara-Bagirmi or further even. Phoible has an inventory for Bagirmi with two central vowels /ʌ ɘ/ as well; and per Rolle, Faytak & Lionnet (2017) central vowels have indeed been considered an areal feature of central Africa, though they follow instead a hypothesis that this is contact-induced in Sara-Bagirmi.

(3) some more or less clear cases of classic Nilo-Saharan / Macro-Sudanic prefix derivatives (no idea how productive any of this remains):

/a˩ndɨ˧/ (àndɨ̄) 'to bear fruit' : /ka˩ndɨ˧/ (kàndɨ̄) 'fruit'

/il˩˧/ (ìl̄) 'to be dark' : /til˩˧/ (tìl̄) 'darkness, invisibility'

/o˩le˧/ (òlē) 'to boil' : /jo˩le˩/ (yòlè) 'to burn hairs'

/õ˩/ (ò̰) 'to eat from a bowl' : /dõ˩/ (dò̰) 'to bite'

Anyway since I have it around, I've been keeping an eye also on the Gumuz languages Swadesh list as I go over Keegan's collection of comparative data. Maybe 6/35 cases so far that look like they could have anything at all to do with each other, but interestingly enough this already suggests one regular correspondence:

'blood': Sara #mʌ˥sɨ˧ ~Gumuz mahá (S), maχá (N)

'far': Sara #sãj˥ ~ Gumuz háat (S), χát (N)

though then unfortunately already a third match disagrees: 'to eat', Sara #ɨ˩sʌ˩ ~ Gumuz sá.