Discussion of accentuation patterns of Greek verbs ending in -ζω and -ιζω, vowel weakening and diphthong behavior, with examples and some dialectal notes (Doric, Thessalian, Marica reference).
ἔπταζον ὥστ´ ὄρνιθες ὦκυν αἴετον ἐξαπίνας φανέντα ἀντὶ τοῦ ἔπτησσον· καὶ τοῦ πλάζω τὸν δ´ ἐπιπλάζοντ´ ἄνεμοι φέροιεν καὶ μελέδωνα ἀντὶ τοῦ ἐπιπλήσσοντα. ἔτι καὶ βαρύνεται τὰ πρὸς τῷ 'α' ἔχοντα τὸ 'ι' σφαδᾴζω, τερᾴζω, ματᾴζω καὶ τὸ παίζω μόνον ἔχον πρὸ τέλους τὴν 'αι' δίφθογγον ἐκφωνουμένην. * Τὰ εἰς 'ζω' παραληγόμενα τῷ 'ε' βαρύνεται, ἕζω, χέζω, ῥέζω, πιέζω μόνον εἰς 'ζω' ὑπὲρ δύο συλλαβὰς βαρύτονον τῷ 'ε' παραληγόμενον, Δωριεῖς πιάζω ἀναλογώτερον. τοῦτο δὲ καὶ ἀπὸ περισπωμένου. τὸ δὲ τραπεζῶ περισπᾶται, ὅτι τράπεζα. * Τὰ εἰς 'ιζω' βαρύνεται, τρίζω, σχίζω, πρίζω, κτίζω, ἵζω, χαρίζω, χωρίζω, βαπτίζω, ὀνειδίζω, αἰκίζω, στηρίζω, θρυλλίζω, λυρίζω, σαλπίζω, συρίζω, χαιτίζω, κιθαρίζω, Δωρίζω, Θετταλίζω, ἀφ´ οὗ τὸ ἐντεθετταλίσμεθα παρὰ τῷ Εὐπόλιδι ἐν Μαρικᾷ, τουτέστι χλαμύδα Θετταλικὴν φοροῦμεν, Σκυθίζω, Περσίζω, σφετερίζω. τὸ δὲ ῥιζῶ περισπᾶται, ὅτι ῥίζα.
They said ἔπταζον, as birds [do] when a swift eagle has suddenly appeared, instead of ἔπτησσον; and from πλάζω [comes] τὸν δ᾽ ἐπιπλάζοντ᾽ ἄνεμοι φέροιεν καὶ μελέδωνα, instead of ἐπιπλήσσοντα. Further, those with ι before α are also accented with a grave: σφαδᾴζω, τερᾴζω, ματᾴζω; and παίζω alone has the diphthong αι before the end pronounced. Those ending in -ζω with ε in the penult are accented with a grave: ἕζω, χέζω, ῥέζω; πιέζω alone among the -ζω verbs of more than two syllables, with ε in the penult, is barytone; the Dorians [say] πιᾴζω, more in accordance with analogy. This too is derived from a circumflexed form. τραπεζῶ, however, is circumflexed, because [it comes from] τράπεζα. Those ending in -ιζω are barytone: τρίζω, σχίζω, πρίζω, κτίζω, ἵζω, χαρίζω, χωρίζω, βαπτίζω, ὀνειδίζω, αἰκίζω, στηρίζω, θρυλλίζω, λυρίζω, σαλπίζω, συρίζω, χαιτίζω, κιθαρίζω, Δωρίζω, Θετταλίζω—from which [comes] ἐντεθετταλίσμεθα in Eupolis’ Maricas, that is, ‘we wear a Thessalian cloak’—Σκυθίζω, Περσίζω, σφετερίζω. ῥιζῶ, however, is circumflexed, because [it comes from] ῥίζα.