PROTO-INDO-EUROPEAN
ROOT
EXTENSIONS
• Hitt. kappilae- 'pick a fight'? (EDHIL: 439f.)
• Luv. kapilala- 'enemy' (EDHIL: 439f.)
• CLuv. kappilazza- 'become hostile' (EDHIL: 439f.) Kloekhorst argues that CLUw. kappilazza- cannot go back to the root *ḱep-, since the the reflex of this root in Luwian hsould have started with *zapp-.
References
EDHIL = Kloekhorst, A. 2008. Etymological Dictionary of the Hittite Inherited Lexicon. Brill.