Third-person plural present/middle forms end in -σι/-ι; accent shifts when enclitic or due to syllable count; examples: λέγομεν/λέγετε/λέγουσι, ἵσταμεν/ἵστασι, changes with ἴασι/ἴμεν and enclitics; rules for optatives in -μι and accent patterns for aorist, perfect, etc.
* Τὰ τρίτα πληθυντικὰ ἐνεστῶτος χρόνου ἢ μέλλοντος εἰς 'ι' λήγοντα θέλει ὁμοτονεῖν ταῖς πληθυντικαῖς δοτικαῖς τῶν μετοχῶν, ὁπότε καὶ ὁμοφωνοῦσιν, λέγομεν λέγετε λέγουσι καὶ τοῖς λέγουσιν, ἵσταμεν ἵστατε ἱστᾶσι καὶ τοῖς ἱστᾶσιν, ἵεμεν ἵετε ἱεῖσι· καὶ γὰρ ἱέντες ἱέντων ἱεῖσι, λέξομεν λέξετε λέξουσι καὶ τοῖς λέξουσι, διδοῦσιν ἐκεῖνοι καὶ τοῖς διδοῦσιν, ζευγνῦσιν ἐκεῖνοι καὶ τοῖς ζευγνῦσιν. ἀντιπίπτει μόνον τὸ φασί πρὸς τὸ φᾶσι μετοχικὸν ὡς στᾶσι. τὸ δὲ αἴτιόν ἐστιν, ὅτι τοῦτο ἐγκλιτικόν, τὰ δὲ ἐγκλιτικὰ αὐτὰ καθ´ ἑαυτὰ ὄντα ἐν τῇ τελευταίᾳ συλλαβῇ θέλουσιν ἔχειν τὸν τόνον, φημί, εἰμί, ἐστί. * Τὰ εἰς 'σι' παραληγόμενα τῷ 'α' προπερισπᾶται, πιμπρᾶσι, κιχρᾶσι, ἱστᾶσι· καὶ ζητοῦσί τινες, τίνος χάριν οὐ περισπᾶται «καί τ´ ἀγεληδὸν ἴασι» (Π 160) καὶ λέγομεν, ὅτι τὰ προπερισπώμενα ἰσοσυλλαβεῖ τοῖς πρώτοις, ἱστᾶσι ἵσταμεν, κιχρᾶσι κίχραμεν, τὰ δὲ πλεονάζοντα τρίτην ἀπὸ τέλους ἔχει τὴν ὀξεῖαν, δίδομεν διδόασι, τίθεμεν τιθέασιν, ἐν οἷς οὖν τὸ ἴασι πλεονοσυλλαβεῖ τοῦ ἴμεν, ἐν τούτοις καὶ προπαροξυνθήσεται. ἔστι καὶ οὕτως εἰπεῖν περὶ τοῦ ἴασιν· πᾶν πληθυντικὸν εἰς 'μεν' λῆγον, ὅτε ἐστὶ ἀπὸ τῶν εἰς 'μι', μεταποιεῖ τὸ τρίτον τῶν πληθυντικῶν εἰς 'ασι' προπαροξυνόμενον, τίθεμεν τιθέασι, δίδομεν διδόασι, ἵεμεν ἱέασι, ἔμεν ἔασι, ζεύγνυμεν ζευγνύασιν· εἰ οὖν ἐστιν ἴμεν, σαφὲς ὅτι τῇ αὐτῇ ἀκολουθίᾳ καὶ τὸ ἴασι προπαροξυτονηθήσεται. ἔστι δὲ ἀπὸ τοῦ εἶμι τὸ πορεύομαι τὸ πληθυντικὸν ἴμεν διὰ τοῦ 'ι'. Τὰ εἰς 'μι' εὐκτικὰ ἀποστρέφονται τὴν ὀξεῖαν τάσιν, τύπτοιμι, τύποιμι, ποιοῖμι, χρυσοῖμι, βοῷμι. Τὰ δεύτερα καὶ τὰ τρίτα τῶν εἰς 'μι' εὐκτικῶν ὁμοτονοῦσι τοῖς ἰδίοις πρώτοις, τύπτοιμι τύπτοις, τύπτοι, ποιοῖμι ποιοῖς ποιοῖ, βοῷμι βοῷς βοῷ. Πᾶς παρῳχημένος ὁριστικὸς εἰς 'α' λῆγον ὑπερδισύλλαβος ἁπλοῦς προπαροξύνεται, τέτυφα, πεποίηκα παρακείμενος. ὁμοίως καὶ ὁ ἀόριστος ἔτυψα ἐποίησα. τὸ δὲ ἧψα καὶ οἶδα δισύλλαβα, καὶ τὸ συνῆψα σύνθετον. τὸ δὲ ἐφοίτα ἀπὸ τοῦ ἐφοίταε τὸ 'α' μακρόν. Τὰ εἰς 'θα' ἐν δευτέραις προσώποις ὑπερδισύλλαβα προπαροξύνεται,
The third plural forms of the present tense or the future ending in -ι are required to have the same accent as the plural datives of the participles, whenever they also agree in sound: λέγομεν λέγετε λέγουσι and τοῖς λέγουσιν, ἵσταμεν ἵστατε ἱστᾶσι and τοῖς ἱστᾶσιν, ἵεμεν ἵετε ἱεῖσι; for ἱέντες ἱέντων ἱεῖσι; λέξομεν λέξετε λέξουσι and τοῖς λέξουσι, διδοῦσιν ἐκεῖνοι and τοῖς διδοῦσιν, ζευγνῦσιν ἐκεῖνοι and τοῖς ζευγνῦσιν. Only φασί is an exception in relation to the participial φᾶσι, as στᾶσι. The reason is that this is enclitic; and enclitics, when they stand by themselves, wish to have the accent on the last syllable: φημί, εἰμί, ἐστί.
Forms ending in -σι with α in the penult are circumflexed on the antepenult: πιμπρᾶσι, κιχρᾶσι, ἱστᾶσι. And some inquire why «καί τ᾽ ἀγεληδὸν ἴασι» (Π 160) is not circumflexed; and we say that the forms circumflexed on the antepenult are equal in syllables to the first persons: ἱστᾶσι ἵσταμεν, κιχρᾶσι κίχραμεν; but the forms with an extra syllable have the acute on the third from the end: δίδομεν διδόασι, τίθεμεν τιθέασιν; therefore, since ἴασι has more syllables than ἴμεν, in these cases it will also be accented on the antepenult. It is also possible to speak thus about ἴασιν: every plural ending in -μεν, when it is from verbs in -μι, changes the third plural into -ασι with accent on the antepenult: τίθεμεν τιθέασι, δίδομεν διδόασι, ἵεμεν ἱέασι, ἔμεν ἔασι, ζεύγνυμεν ζευγνύασιν. If, then, there is ἴμεν, it is clear that by the same sequence ἴασι too will be accented on the antepenult. And ἴμεν, the plural of πορεύομαι, is from εἶμι, with ι.
Optatives in -μι avoid the acute accent: τύπτοιμι, τύποιμι, ποιοῖμι, χρυσοῖμι, βοῷμι. The second and third persons of optatives in -μι have the same accent as their own first persons: τύπτοιμι τύπτοις, τύπτοι; ποιοῖμι ποιοῖς ποιοῖ; βοῷμι βοῷς βοῷ.
Every past indicative ending in -α, of more than two syllables, simple, is accented on the antepenult: τέτυφα, πεποίηκα (perfect). Likewise also the aorist ἔτυψα, ἐποίησα. But ἧψα and οἶδα are disyllabic, and συνῆψα is compound. And ἐφοίτα, from ἐφοίταε, has long α.
Forms in -θα in second persons, of more than two syllables, are accented on the antepenult.