clango.

Likely related to Ancient Greek κλᾰ́ζω (klắzō, “make a sharp noise”, verb) and κλᾰγγή (klăngḗ, “shrill sound”, noun). The details and further cognates are uncertain. Schrijver 1991 derives both Latin clang- and Greek κλᾰγγ- (klăng-) from Osthoff's Law shortening of earlier *klāng-, from *klh₂-n-g-, from a root *klh₂g- with a nasal infix *-n-. However, Schrijver is hesitant about reconstructing the root due to its expressive nature. In contrast, Beekes 2010 rejects *klh₂g-, saying it would produce a Greek form in *κλᾱγ- (*klāg-) rather than κλᾰγ- (klăg-), and rejects *klag­- for having *a (which Beekes does not accept as a PIE phoneme). Beekes concludes that the root "must have been adopted from a non-IE language", and compares Old Norse hlakka (“to cry”) as another possible cognate, suggesting that its geminate -kk- could go back to original -*-nk-.