mwh wrote:(Accentuation of the present tense of ειμί is a mess. Most editors, on little or no ancient authority, differentiate between the regular and the “existential” forms, έστι etc., in the disyllables, cf. ἔστιν ὅτε in the recent thread. After ου ancient grammatical doctrine prescribed έστι. I don’t know why ούκ εστι (or ουκ εστί) was disallowed; that doesn’t seem to make linguistic sense.)
Chandler has some discussion and points to Hermann for a simplifying assumption, but there’s not much light.
In Japanese, desu (the copula), moves between accents depending on the words around it, depending on whether it rubs up against unvoiced consonants. It’s not that the languages are related, but that the level of complexity that we should expect is very high.
It’s worthwhile reading through Samuel E. Martin’s 1967 paper “On the Accent of Japanese Adjectives” to get an idea of how complicated pitch accent is in a mora-timed language with single-accent words. The complexities and irregularities are far greater than anything that has come down to us about Greek.
It makes me think that everything that the grammarians wrote could well be true, or mostly true, especially compared to the simplifying rules of modern editors. The vast majority of the complexity of Greek’s accent system is probably unavailable to us, and in the rules that we do know, we are only seeing a scattering of the most prominent features.