Accentuation rules for -ι, -ου, -τι and related endings; cases of oxytone vs barytone, expansion (ἐπέκτασις), loss of σ before -ις, examples (Ἰαστί, Δωριστί, πολλάκι, etc.).
παράδοσις ἔχει τὸ 'ι'. ναίχι, ὅπερ παροξύνεται διὰ τῆς 'χι' ἐπεκτεταμένον. ἐχρῆν δὲ καὶ τὸ οὐχί βαρύνεσθαι· ἔστι γὰρ ἐπέκτασις τῆς οὔ. ἀλλ´ ἐπειδὴ παραλόγως ὀξύνεται πρὸ τῆς ἐπεκτάσεως—ὤφειλε γὰρ περισπᾶσθαι, ἐπεὶ πᾶσα συλλαβὴ τελικὴ εἰς 'ου' λήγουσα καὶ ἐφ´ ἑαυτῆς τὸν τόνον ἔχουσα περισπᾶται—τούτου χάριν παραλόγως ὀξύνεται καὶ μετὰ τὴν ἐπέκτασιν· οὐδέποτε δὲ ἀποβολὴν τοῦ 'ι' πάσχει. ὀξύνεται δὲ καὶ τὸ οὐκί καὶ τὸ πρωΐ. καὶ τὸ γίγγρι ἐπιφώνημά τι ὂν ἐν καταμωκήσει λεγόμενον, εἰ ὠξύνετο, οὐκ ἄτοπον. ἀχαρακτήριστον γάρ ἐστιν. τὸ δὲ »χῶρι διατμήγουσι« (Callim. fr. 48 Bentl.) βαρύνεται. τὰ ὑπὲρ δύο συλλαβὰς εἰς 'τι' ὀξύνεται, Ἰαστί, Ἰαονιστί, Δωριστί, Συριστί, Ἀττικιστί, Μεγαριστί, Θρᾳκιστί, Περσιστί, Σκυθιστί, Λυδιστί, Φρυγιστί, μεγαλωστί, ἱερωστί, νεωστί, δημιωστί. εἰ δὲ μὴ ἔχοι τὸ 'σ' πρὸ τοῦ 'τ', βαρύνεσθαι θέλει, ἕκητι. τὸ δὲ ἀπαρτί παρ´ Ἀθηναίοις ὀξύνεται καὶ τὸ ἐγκυτί »σὺ δ´ ἐγκυτὶ τέκνον ἐκέρσω« (Callim. fr. 311 Bentl.). τὸ ἱνατί καὶ διατί καὶ ἐν τῇ συνεπείᾳ ὀξύνεται. Καὶ τὰ ἀπὸ τῶν εἰς 'ις' κατ´ ἀποβολὴν τοῦ 'ς' βαρύνεται, πολλάκι, τουτάκι, θαμάκι, δυάκι, τριάκι, ἑξάκι. Τὰ εἰς 'υ' λήγοντα δισύλλαβα, μὴ καθαρεύοντα μηδὲ μελετήσαντα τὸ 'ς' ἔχειν, βαρύνεται, κόκκυ τὸ ἐλάχιστον, πάγχυ, πρόχνυ, δεῦρυ, πῆλυ, ἄρρυ ἐπίφθεγμα τῶν ἐρετῶν. τὸ ἰύ, ὃ λέγεται καὶ ἰηΰ, ὀξυνόμενον καθαρεύει ἐπὶ θαύματος κείμενον. τὸ δὲ ἔϋ βαρύνεται· ἔστιν ἐΰς ἐΰ εὖ καὶ ἀπὸ τοῦ εὖ κατὰ διάλυσιν τῆς 'ευ' διφθόγγου εἰς 'ε' καὶ
Tradition has the ‘ι’: ναίχι, which is accented on the penult, being extended by the ‘χι’. But οὐχί too ought to be barytone; for it is an extension of οὔ. But since, contrary to rule, it is accented acute before the extension—for it ought to have a circumflex, since every final syllable ending in ‘ου’ and having the accent on itself takes a circumflex—for this reason it is, contrary to rule, accented acute also after the extension; and it never suffers loss of the ‘ι’. And οὐκί and πρωΐ are also accented acute. And γίγγρι, being an interjection uttered in mockery, if it were accented acute, would not be out of place; for it is without fixed accentuation. But »χῶρι διατμήγουσι« (Callim. fr. 48 Bentl.) is barytone. Forms of more than two syllables ending in ‘τι’ are accented acute: Ἰαστί, Ἰαονιστί, Δωριστί, Συριστί, Ἀττικιστί, Μεγαριστί, Θρᾳκιστί, Περσιστί, Σκυθιστί, Λυδιστί, Φρυγιστί, μεγαλωστί, ἱερωστί, νεωστί, δημιωστί. But if it does not have ‘σ’ before ‘τ’, it wants to be barytone: ἕκητι. But ἀπαρτί among the Athenians is accented acute, and ἐγκυτί: »σὺ δ´ ἐγκυτὶ τέκνον ἐκέρσω« (Callim. fr. 311 Bentl.). ἱνατί and διατί and, in consequence, are accented acute. And those derived from words in ‘ις’ by loss of the ‘ς’ are barytone: πολλάκι, τουτάκι, θαμάκι, δυάκι, τριάκι, ἑξάκι. Disyllables ending in ‘υ’, not pure and not having practiced having ‘ς’, are barytone: κόκκυ, the least; πάγχυ, πρόχνυ, δεῦρυ, πῆλυ, ἄρρυ, an exclamation of the rowers. ἰύ, which is also said ἰηΰ, when accented acute is pure, being used in expressions of wonder. But ἔϋ is barytone; it is ἐΰς ἐΰ εὖ, and from εὖ by resolution of the ‘ευ’ diphthong into ‘ε’ and…