conc▪ Accord. to Ehret1989 #21 an extension in »iterative« *‑ḥ from a 2-rad. pre-protSem root ↗*SL ‘to draw out or off’, preserved in Ar ↗salla ‘to draw out slowly’. Other extensions from the same basis would include ↗salaʔa, ↗salaba, ↗salata, ↗salaḫa, ↗saliʕa, ↗salafa, ↗salaqa.