PS

*gŝˁ/ˀ - to belch, retch, vomit (SED I No. 17ᵥ)

Akkadian
gešû - to belch (CAD G 64, AHw. 287)
Hebrew
gˁš - (hitpo.) to vomit loudly (HALOT 200)
Cf. Hbr. pB. gˁš ‘to cough or sneeze’ (Jastrow 261) with a meaning shift.
Syriac
gsy - to spit out, belch, vomit (LSyr. 126, SL 250)
Mandaic
gsa, gus - to vomit, to belch (MD 96, 84)
Arabic
ǯˁs - to deposit excrements (BK 1 300, Lane 429)
A variant root with a meaning shift?
Arabic
ǯšˀ - to burp (BK 1 295, Lane 426)
Geez
gʷäŝˁa - to belch, vomit (CDG 205)
Tigre
gäsˁa - to belch (WTS 580)
Amharic
gässa - to belch, to emit blood (AED 1954)
Argobba
(as)gessa - to belch (Leslau 1997: 203)
Harari
giziˀ āša - to belch (EDH 77)
With unexpected -z-.
Selti
atgēsä - to belch (EDG 297)
Wolane
atgesä - to belch (EDG 297)
Zway
(a)gäsa - to belch (EDG 297)
Chaha
(a)gäsa - to belch (EDG 297)
Ezha
agässa - to belch (EDG 297)
Endegen
agässaˀa - to belch (EDG 297)
Gyeto
(a)gäsa - to belch (EDG 297)
Muher
agässa - to belch (EDG 297)
Masqan
agässa - to belch (EDG 297)
Gogot
agässa - to belch (EDG 297)
Soddo
agässa - to belch (EDG 297)
Mehri
gǝŝō - to belch, eructate (ML 126)
Jibbali
s̃ǝgéŝi (caus.-refl.) - to belch (JL 80)
Harsusi
geŝō - to belch (from over-eating) (HL 42)