Lionello, well, I am a lowland Scot so probably have a fair bit of Anglo-Saxon blood in my veins!
Eliza, I am familiar with Yorkshire people using ‘aye’ for yes, but wasn’t aware that the other meaning - always - was also current there?
For clarity, I still use and hear the word daily in both senses when back in Scotland.
The always one seems to go back a fair way and the yes one may even come from the always one. Here’s what Etymonline says about the two:
“assent,” 1570s, of unknown origin, perhaps a variant of I, meaning “I assent;” or an alteration of Middle English yai “yes” (see yea), or from aye (adv.) “always, ever.”
“always, ever,” c.1200, from Old Norse ei ”ever" (cognate with Old English a ”always, ever"), from PIE *aiw- “vital force, life, long life, eternity” (cf. Greek aion ”age, eternity,” Latin aevum ”space of time;” see eon).