PS

*šumū̆ - they (masc.) (Kogan 2009:68)

For the distribution of the initial š- and h- in individual languages see *šū̆/šū̆ˀ/šū̆wa (compare also the initial ˀ- in BArm). In individual languages there are different ways of opposing the masculine form of the 3 pl. pronoun to the feminine one. In Akk. and BArm. the two forms are opposed through the vocalic contrast in the second and third syllables (masc. -u-...-u vs. fem. -i-...-a) with no consonantal contrast (-n- in both genders). In Arb., Hrs. and Jib. the gender opposition is provided by the third consonant (masc. -m- vs. fem. -n-) alongside with some vocalic differences. The mere consonantal opposition is present in Hebrew and Mehri. See Kogan 2009:66–68.

Akkadian
šunu - they (masc.) (CAD Š₃ 304, AHw. 1277)
Hebrew
hēm/hēmmā - they (masc.) (HALOT 250)
Biblical Aramaic
ˀinnūn - they (masc.) (HALOT 1817)
Arabic
hum - they (masc.) (BK II 1442)
Geez
ˀəmmuntu - they (masc.) (CDG 25)
The pronoun probably goes back to PWS *humū with the extension through the deictic elements -n-t-u, present in other types of Geez pronouns. The shift *h- > ˀ is irregular (Kogan 2009:68).
Mehri
hēm - they (masc.) (ML 157)
Jibbali
šum - they (masc.) (JL 262)
Harsusi
hōm - they (masc.) (HL 51)