-humā - of them both; both of them (genitive and accusative pronominal suffix, 3 du.) (Fischer 2002 § 268)

3 du. pronominal suffixes are also present in Akkadian (see -šunī) 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).