Sorry. Early modern english and redneck.
Speaking of thee and thou, you sound like you might know this answer. I read somewhere that there was a Norse? letter for ‘th’ that resembled a ‘Y’, and that when typesetting began, a ‘Y’ was often used for it, so we ended up with ‘Ye Olde..., but would have been pronounced ‘The’. Any idea about the veracity of that theory?
We have a few "methinks" crop up in posts. Now I know why.
I think that the letter from olde English/Norse you are referring to is named *Thorne*. It looks like this:
Þ
and as you say, is pronounced like “th” in the or there.
To get the letter to print like I did, hold down your alt key and using the numeric keypad type 0222
I checked my dictionary and it indicates as you say except that the character substituted an old english character, not norse.
However, as the language changed primarily due to those pesky normans, it may very well have norse origin as you indicate.
Speaking like that in a bar-“ I’ll have a whithkey thtone thour, pleathe”