Discussion of Ancient Greek accentuation rules and vowel/diphthong behavior (ει, η, ευ, αυ, ει→ει changes), accent patterns in compounds and genitives, Boeotian vowel shifts, treatment of monosyllables, and examples of personal/place names and ethnics ending in -ευς, -εύς, -εῖς, and -αι.
δὲ κατὰ τὴν παράδοσιν διὰ τῆς 'ει' διφθόγγου καὶ βαρύνεται, τῶν ἄλλων θηλυκῶν ὑπὲρ μίαν συλλαβὴν κοινῶν τὴν 'ει' δίφθογγον ἀποστρεφομένων καὶ ὀξυνομένων ὡς ῥανίς βολίς θυρίς. αἱ δὲ μετοχαὶ ὀξύνονται τυφθείς, τυπείς, δαρείς. τὸ δὲ κτείς ὀξύτονον ὡς μονοσύλλαβον καὶ τὸ κλείς. τοῦτο δὲ ἐν τῇ συνθέσει βαρύνεται οἷον κατάκλεις. καὶ οἱ Βοιωτοὶ τὸ 'η' τῶν εἰς 'ης' εἰς 'ει' τρέποντες ὀξύνουσι τὰ ὀξύτονα, εὐγενείς ἀντὶ εὐγενής, ἀγενείς ἀντὶ ἀγενής. τὸ δὲ οὐδείς δύο μέρη λόγου εἰσὶ τό τε οὐ καὶ τὸ δείς. οὐδὲ γὰρ ἔστι σύνθετον. εἰ γὰρ ἦν σύνθετον, ἤμελλε πρὸ μιᾶς ἔχειν τὸν τόνον. πᾶν γὰρ ὄνομα μονοσύλλαβον συντιθέμενον ἀναβιβάζει τὸν τόνον παῖς εὔπαις, χθών αὐτόχθων, Θρᾷξ Σαμόθρᾳξ χωρὶς τοῦ πτώξ πολυπτώξ. δηλοῖ δὲ καὶ ἡ γενικὴ ὀξυνομένη. εἰ γὰρ ἦν ἐν συνθέσει, ἤμελλεν ἡ γενικὴ βαρύνεσθαι. πᾶσα γὰρ γενικὴ ὑπὲρ δύο συλλαβὰς εἰς 'ος' λήγουσα ἀπέστραπται τὴν ὀξεῖαν τάσιν χωρὶς τοῦ γυναικός καὶ θυγατρός. Τὰ εἰς 'αυς' πολυσύλλαβα βαρύνονται, χιλιόναυς, ὠμόγραυς. τὰ δὲ ἁπλᾶ περισπῶνται γραῦς, ναῦς. Τὰ εἰς 'ευς' κοινῶς μὲν ὀξύνεται, βασιλεύς, Πηλεύς, Τυδεύς, ἀριστεύς, Περσεύς, Πορθεύς, Πρωτεύς, ἁλιεύς, οἰνεύς, Λυγκεύς, Ἀχιλλεύς, Τηρεύς, Θησεύς, Ὀδυσσεύς. ἔστι καὶ πόλις Ἰβηρίας Ὀδυσσεῖς ἀρσενικῶς. Βρισεύς, Ἀτρεύς. Λεοντεύς, Αἰθιοπεύς, ἐξ οὗ τὸ Αἰθιοπῆας παρ´ Ὁμήρῳ (Il. Α 423), ἀγυιεύς ὁ τοπίτης. λέγονται καὶ ὀβελίσκοι θεοῖς ἀνειμένοι, ὡς Εὔπολις. λέγεται καὶ κίων ἀγυιεύς εἰς ὀξὺ ἀπολήγων, ὁ πρὸ τῶν θυρῶν ἱστάμενος. Ἀριστοφάνης Θεσμοφοριαζούσαις (v. 489) καὶ ὁ Ἀπόλλων ἀγυιεύς τουτέστιν ὁ ἐφόδιος. Μοψοπιεύς, Ἐρετριεύς, Φωκαιεύς, Θεσπιεύς, Ἀλεξανδρεύς, Ἀντιοχεύς, Σελευκεύς, Αἰγιαλεύς. εὑρίσκεται δὲ καὶ αἰγιαλεύς ἐπὶ ἰχθύος. Αἰγικορεῖς, Ἀργαδεῖς φυλαὶ παλαιαί. Αἰθυσσεῖς ἔθνος Λιβυκὸν Μαρμαρίδαις πάροικον, ὡς Ῥιανός. Αἰολεύς. οὕτως λέγονται οἱ τὴν Λέσβον οἰκοῦντες ἀπὸ τῶν Αἰόλου παίδων ὡς Δωριεῖς ἀπὸ τῶν Δώρου. Ἁλιεῖς πόλις Ἀργολικῆς παραθαλασσία καὶ τὸ ἐθνικὸν ὁμοίως. Ἔφορος ἐν τῷ ἕκτῳ »Τιρύνθιοί εἰσιν οὗτοι καὶ ἐξαναστάντες ἐβουλεύοντο οἰκεῖν τινα τόπον καὶ ἠρώτων τὸν θεόν. ἔχρησε δ´ οὕτως «ποῖ τυ λαβὼν καὶ ποῖ τυ καθίξω καὶ οἴκησιν ἔχων ἁλιέα τε κεκλῆσθαι». ἐλέγοντο δ´ οὕτως διὰ τὸ πολλοὺς τῶν Ἑρμιονέων ἁλιευομένους κατὰ τοῦτο τὸ μέρος οἰκεῖν τῆς χώρας. Ἀντικονδυλεῖς οἱ ἐν Βοιωτίᾳ Κολοίφρυγες, ὡς Ἀριστοφάνης ὁ τοὺς Θηβαίων ὥρους γεγραφώς. Αὐσεῖς ἔθνος Λιβύης. Ἀπολλόδωρος δευτέρᾳ περὶ γῆς καὶ Ἡρόδοτος ἐν τετάρτῃ (c. 180). Γαργαρεῖς ἔθνος, ὃ μίγνυται ταῖς Ἀμαζόσιν, ὡς Στράβων
But according to the tradition it is written with the 'ει' diphthong and is also barytone, since the other feminine nouns of more than one syllable reject the 'ει' diphthong and are oxytone, as ῥανίς, βολίς, θυρίς. The participles, however, are oxytone: τυφθείς, τυπείς, δαρείς. But κτείς is oxytone as a monosyllable, and so is κλείς. In composition, however, this is barytone, e.g. κατάκλεις. And the Boeotians, turning the 'η' of words in -ης into 'ει', accent the oxytones as oxytones: εὐγενείς instead of εὐγενής, ἀγενείς instead of ἀγενής. But οὐδείς consists of two parts of speech, οὐ and δείς; for it is not a compound. For if it were a compound, it would have the accent on the antepenult. For every monosyllabic noun when compounded raises the accent: παῖς → εὔπαις, χθών → αὐτόχθων, Θρᾷξ → Σαμόθρᾷξ, except πτώξ → πολύπτωξ. The genitive too, being oxytone, makes this clear; for if it were in composition, the genitive would be barytone. For every genitive of more than two syllables ending in -ος has rejected the acute accent, except γυναικός and θυγατρός. Polysyllables in -αυς are barytone: χιλιοναυς, ὠμόγραυς; but the simple forms are circumflexed: γραῦς, ναῦς. Words in -ευς are generally oxytone: βασιλεύς, Πηλεύς, Τυδεύς, ἀριστεύς, Περσεύς, Πορθεύς, Πρωτεύς, ἁλιεύς, οἰνεύς, Λυγκεύς, Ἀχιλλεύς, Τηρεύς, Θησεύς, Ὀδυσσεύς. There is also a city of Iberia, Ὀδυσσεῖς, masculine. Βρισεύς, Ἀτρεύς; Λεοντεύς, Αἰθιοπεύς, from which comes Αἰθιοπῆας in Homer (Il. Α 423); ἀγυιεύς, the local epithet. There are also said to be small spits dedicated to the gods, as Eupolis says. And a pillar is also called ἀγυιεύς, ending in an acute, the one set up before doors. Aristophanes in the Thesmophoriazusae (v. 489): “and Apollo ἀγυιεύς,” that is, the god of the road. Μοψοπιεύς, Ἐρετριεύς, Φωκαιεύς, Θεσπιεύς, Ἀλεξανδρεύς, Ἀντιοχεύς, Σελευκεύς, Αἰγιαλεύς; and αἰγιαλεύς is also found of a fish. Αἰγικορεῖς, Ἀργαδεῖς, ancient tribes. Αἰθυσσεῖς, a Libyan people dwelling near the Marmaridae, as Rhianus says. Αἰολεύς: thus are called those who inhabit Lesbos, from the children of Aeolus, just as the Δωριεῖς are from the children of Dorus. Ἁλιεῖς, a coastal city of the Argolid, and the ethnic name likewise. Ephorus in the sixth book: “These are Tirynthians, and after rising up they were planning to settle in some place and were asking the god. And he gave an oracle thus: ‘Whither shall I take you, and whither shall I set you down, and, having a dwelling, be called both ἁλιεύς?’” And they were called thus because many of the Hermionians, fishing, lived in that part of the country. Ἀντικονδυλεῖς, the Κολοίφρυγες in Boeotia, as Aristophanes, who wrote the boundaries of the Thebans, says. Αὐσεῖς, a people of Libya: Apollodorus in the second book On the Earth, and Herodotus in the fourth (c. 180). Γαργαρεῖς, a people who mingle with the Amazons, as Strabo says.