Tell me if you want me to post this at ELU -- but please don't downvote me into oblivion. I'm happy to delete here and repost there if need be.
I thought I could explain to English speakers how to pronounce the pure E of Spanish as in meta by referencing the Canadian "eh," but it turns out that doesn't work because apparently the Canadian "eh" is a diphthong. See https://english.stackexchange.com/q/363302/112436.
So how do others explain this in writing? (If I'm explaining live, I can just demonstrate, obviously.)