Why do we say "hello"?

Picked one by one from a mixed channel. Transcript check: both title readers certain; 5 of 5 sampled certain picks confirmed by transcript, none failed. Channel rule: Include only single-topic etymology episodes with plainly descriptive titles (e.g. idiom origins, word myths, Greek, German or Arabic loanwords, alphabet and writing systems, country, currency or name origins); exclude facts compilations, 'funniest'/'best of' lists, hook-style titles, and any live, bonus or announcement uploads.

A 31-minute video from Words Unravelled: “Why do we say "hello"?”.

Video by Words Unravelled, played through YouTube's embedded player.