An Etymological Dictionary of the German Language/Klang
Klang, m., ‘sound, clang,’ from the equiv. MidHG. klanc (gen. klanges), m., with the variant klanc (gen. klankes), OHG. chlang; comp. Du. klank, m., ‘clang, sound,’ as well as E. clank and clang; AS. *clong, *clonc, are wanting, so too Goth. *klaggs and *klagks; comp. also MidHG. klunc (klunges), m., ‘sound,’ and klinc (klinges), m., ‘tone, clangour.’ The form klank with a final k is to be regarded perhaps like falzen compared with falten, Zicke with Ziege, and Kitze with OIc. kið (comp. also krank), i.e., k represents kk for Aryan kn; glank (or rather glangh) is perhaps the Aryan root of the Teut. cognates, unless we are tempted to regard Klang (comp. klingen) as a new onomatopoetic word (comp. Gr. κλαγγή, Lat. clangor).