@dave me too. Hard to know what speech sounded like 200 years ago, let alone 2-4000. But yeah the X circumscribed by O character has me curious. I scrolled through Unicode for a bit and found ᳁ in the "Sudanese supplement" though it could've been one of the characters my fonts don't render.

@travisfw @dave that’s just Theta Θ. «The form of Ζ generally had a straight stem () in all local alphabets in the archaic period. Θ was mostly crossed ( or ). Ξ typically had a vertical stem (), and Φ was most often . Υ and Ψ had frequent variants where the strokes branched out from the bottom of the character, resulting in and respectively.» See Glyph shape section for images of the letters: https://en.wikipedia.org/wiki/Archaic_Greek_alphabets#Glyph_shapes