Flags have in common with nunchakus and flails, used for threshing, the fact that they are mobile elements attached to sticks. In English, a phonetic similarity between the words “flag” and “flail” inspired me to look into the Indo-European origins of the words.
The root “PLÂG 1 : slow, limp, flaccid” produces the English word “flag” which also means “to languish, to wane and to weaken”. In the same way, in the Nordic languages, we find “vlag / vleg” for “flag”, and the prefix “flakk” which evokes wandering and vagrancy.
As for “flail” and “fléau” (“flail” in French), they both come from “BHLAG” : to “make a noise”, from which comes the Latin “flagrum” : a sort of whip, “flagrio” : slave and “flagello” : to whip. In the same vein there is “flog” in English, “flageller” in French, and also, more unusual the “flagellum” of the spermatozoon.
But the strangest of all, is the second meaning of the French “fléau”, “calamity”, which translates into English as “plague” the Indo-European root of which is a homonym of “flag”. This is “PL ÂG 2 : beat, hit”.
In Antiquity, Egyptians, Greeks and Romans “would beat their chests as a sign of mourning” and this gives the Latin “plangere”. From which many words derive such as “pleurs”, “plaies” and “plaintes” in French, from the Spanish “planir” to the Russian “plakati”, from the Italian “compiangere” to the English “complain”, and the German “fluchen” : to curse, to swear”.
A fine family, don’t you agree ?