-ki - you; your (accusative and genitive pronominal suffix, 2 du.) (ML 219)

2 du. pronominal suffixes are also present in Akkadian (see -kunī) and Arabic (see -kumā). Akkadian and Arabic forms are based on the plural masculine form, while in MSA 2 du. pronominal suffixes are formed on the basis of the singular. Non-Semitic Afroasiatic evidence (see Eg. -ṯny) points at the primary nature of Akkadian-Arabic picture (Kogan 2009:69).