PS

*ḥmṣ̂ - to be sour (Fronzaroli 1971: 623, 635, 641; Kogan 2011: 239)

Akkadian
emēṣu - to be sour (AHw. 214)
Ebla
ˀà-me-ṣu, ˀà-mi-ṣu-um - Sum. NINDA.AD₆ (‘leavened bread’) (VE 128; Conti 1990: 83)
Ugaritic
ḥmṣ - vinegar (DUL 364)
Hebrew
ḥmṣ - to be leavened (HALOT 329)
Hebrew
ḥōmäṣ - vinegar (HALOT 329)
Jewish Palestinian Aramaic
ḥmˁ - to be sour (DJPA 206)
Syriac
ḥmˁ - to ferment, rise (LSyr. 240, SL 466)
Arabic
ḥmḍ - to be sour (Lane 644)
Amharic
may be related
Mehri
ḥāməẑ - to be sour (ML183)
Jibbali
hĩẓ̂ - (milk) to begin turning into butter (JL 112)