conc▪ Etymology obscure. Any relation to any of the main values attached to the root √QLː (QLL), like *‘small, few, insignificant’ (↗¹qalla), *‘to lift, carry’ (↗²qalla), and *‘highest point, summit (↗¹qullaẗ), to rise, separate o.s., seek to stand out’ (↗ĭstaqalla)?
▪ In ClassAr, form X (↗ĭstaqalla) can, among others, also take the value †ʻto become angry; to seize s.o. (fear)’, which seems to be based on ↗¹qullaẗ ʻhighest point, top’, expressing (fig.) usage in the sense of *ʻto seek to overwhelm, sit on top of, overcome s.o.’. So, perh., qill ʻtremor’ is a secondary development, a deverbal back-formation based on ĭstaqalla in the mentioned sense? A denom. derivation of form X †ʻto become angry; to seize s.o. (fear)’ from qill ʻtremor’ would certainly reflect a more usual practice, but given that qill does not seem to have any cognates in Sem nor produced any derivations in Ar, a back-formation from ĭstaqalla is perh. not completely unconceivable.
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