Mehri

ˀətēm - you (m. pl.) (ML 8)

-n- is missing, just in the singular form hēt. Unlike the singular, there is ˀ- instead of the unexplicable h-.

PS
*ˀantumū̆ - you (masc. pl.) (Kogan 2009:67)
In individual languages there are different ways of opposing the masculine form of the 2 pl. pronoun to the feminine one. In Akk. 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 Heb., Arb., Gez., Hrs., Jib. the gender opposition is provided by the third consonant (masc. -m- vs. fem. -n-) alongside with some vocalic differences. The mere consonantal opposition seems to be present only in Mehri. See Kogan 2009:67.