Not unifying them means that the fonts automatically work when you mix text/names written in these alphabets. It also means that mathematical/physical/chemical stuff (that typically uses Latin and Greek letters together) will just work. There is a similar reasoning behind all the mathematical alphabets in Unicode.

Furthermore, Unicode was supposed to handle transcoding from all important preexisting encodings to Unicode and back with no or minimal loss. Since ISO 8859-5 (Cyrillic) and 8859-7 (Greek) already existed (and both included ASCII, hence all the basic Latin letters), the ship had definitively sailed on LaGreCy unification.

On top of that, CJK unification affected so many characters that the savings would really matter and it happened at a time where the codepoints were only 16 bit so it helped squeeze the whole in. All continental European languages suffered equally or worse back when all their letters had to be squeezed into 8 bits /and/ coexist with ASCII.

> Not unifying them means that the fonts automatically work when you mix text/names written in these alphabets. It also means that mathematical/physical/chemical stuff (that typically uses Latin and Greek letters together) will just work.

These are already completely separate symbols. Ignoring precomposition, there are at least 4 different lowercase omegas in unicode: APL (⍵ U+2375 "APL FUNCTIONAL SYMBOL OMEGA"), cyrillic (ѡ U+0461 "CYRILLIC SMALL LETTER OMEGA"), greek (ω U+03C9 "GREEK SMALL LETTER OMEGA") and Mathematics (𝜔 U+1D714 "MATHEMATICAL ITALIC SMALL OMEGA").

Unicode kind of does this already with dotless 'i'; capital 'ı' and lowercase 'İ' are represented as regular latin 'I' and 'i' respectively, despite being semantically different letters.

hungarian "a" is also a separate letter from hungarian "á" but shares the same glyph with english "a" (edit: all vowels are actually considered different letters in their accented form in hungarian, while obviously they are the same letter with a modifier in some latin languages).

(For those who are rusty on their Greek, ω is a lower-case omega, and unrelated to the English/German letter w.)

Cyrillic ПФ vs Greek ΠΦ?

Here's Cyrillic lower case: пф Here's Greek lower case: πφ

in some fonts the pi would be rendered with a longer bar on top, but you just showed why it's a bad idea:

I would want to be able to discuss Greek in Russian on a forum, but this would not be possible because all the glyphs in lowercase would look Russian

The forms 𝜙 and 𝜑 of "lowercase phi" to have different codepoints makes perfect sense to me. That doesn’t mean that upper-case variants of these can’t share a codepoint. As presented elsewhere in this thread, "X.toUpper().toLower()" doesn’t have to be "X". The same holds for "B → b" and "B → β" depending on the context. It’s just that the savings from such a unification would be far smaller due to the smaller sizes of the relevant alphabets.

OK, but you still have a problem because I want to use the same font for Greek and Russian. What if my font is CURSIVE?

Russian and Greek have different cursive forms. You might unify κ and к, but actually the cursive form of κ looks like a Roman u.

So really if this were to happen you'd have "Russian" fonts and "Greek" fonts. Kind of like how Japanese and Chinese have to use different fonts for their languages.

I think their distinct calligraphic representations mean that these would be destructive; whereas with regard to CJK, the characters are clearly represented the same way between the considered languages.