Words

Akkadian
šumma - if (AHw. 1272)

Analyzable as *šim-ma, is to be equated with WS conditional particles (Hbr. ˀim, Arb. ˀin, etc.), which display a well-known shift *š > h > ˀ in (semi-)grammatical morphemes (Voigt 1995).
For the early Akkadian orthographic evidence against *ṯ in the prototype of šumma v. Frayne 1992:633.

Akkadian
summatu - dove (CAD S 380, 1058)
Akkadian
šūmū - garlic (CAD Š₃ 298, AHw. 1275)
Akkadian
šumu - name (CAD Š₃ 284, AHw. 1274)
Akkadian
-šunī - of them both (genitive pronominal suffix, 3 du.) (GAG § 42 i**)
Old Akkadian.
3 du. pronominal suffixes are also present in Arabic (see -humā) and MSA (see Mhr. -hi). Akkadian and Arabic forms are based on the plural masculine form, while in MSA 3 du. pronominal suffixes are formed on the basis of the singular. Non-Semitic Afroasiatic evidence (see Eg. -sny) points at the primary nature of Akkadian-Arabic picture (Kogan 2009:69).
Akkadian
-šunī/-šunīti - both of them (accusative pronominal suffix, 3 du.) (GAG § 42 i**)
Old Akkadian.
Akkadian
-šunīšim - to both of them, for both of them (dative pronominal suffix, 3 du.) (GAG § 42 i**)
Old Akkadian.
Akkadian
sunḳu - famine (CAD S 384)

cf. Syr. snḳ ‘to need, to lack’

Akkadian
šunu - they (masc.) (CAD Š₃ 304, AHw. 1277)
Akkadian
-šunu - their (genitive pronominal suffix, 3 masc. pl.) (GAG § 42 g)