About those “eye rhymes” – Usually if every other set of line endings are the normal sort of rhyme, a poet probably would not insert a single pseudo-rhyme. Also, much early literature, including the Canterbury Tales, was meant to be read aloud and not distributed much in print. So “eye rhymes” would be lost on the intended audience. I’d also like to mention that I always wondered about the practice (in modern songs and poems) of rhyming “again” with words like “rain.” I figured somebody must think they rhyme. And then I heard a British song with those words in it – and “again” indeed does sound like rain. Note that eye rhymes (which do have a technical term; I just can’t remember it) don’t ever turn up in songs, unless the songs are from a time or place where they actually sound alike. Eg, “The boar’s head in hand bear I/bedecked with bays and rosemary” – bet that rhymed at some point.
And for what it’s worth, Egyptian heiroglyphics don’t come with a pronunciation key and Egyptologists have frequently noted that the way we think they talked is probably wrong. BUT, Coptic is Egyptian spelled as accurately as possible in Greek letters. This doesn’t tell us everything, but a lot of what is known about egyptian pronunciation comes from Coptic transliteration. For example, the S sound in the name of the board game senet was probably pronounced more like a Z.