PWS

*ḫāḫ- - plum tree (Fronzaroli 1969: 7, 25, 33)

The form should be probably postulated for PWS level, since there are chances that Akkadian ḫaḫḫu is a West Semitic loanword, s. Kogan 2012: 255

Akkadian
ḫaḫḫu - plum tree; peach tree (CAD Ḫ 29, AHw. 308, CDA 101)
See most recently Kogan 2012a:254f.
Syriac
ḥaḥḥā, ḥōḥā - plum tree (LSyr. 226, SL 441)
Arabic
ḫawḫ- - plum tree (Lane 820)
Geez
ḫoḫ - plum tree (CDG 260)