Discussion of accentuation patterns for words ending in -οι and -αι, especially place/directional forms and disyllables: when they are perispastai or barium occurs, with numerous examples (Μεγαροῖ, Πυθοῖ, σφιγγοῖ, βυθοῖ, ἁρμοῖ, etc.) and notes on other particles like οὐαῖ, αἰαῖ.
μὲν εὐλόγως παρὰ βαρυτόνου τοῦ ὥρα, οὐκ ἔχει δὲ προϋποκείμενον εἰς 'θεν'. Τὰ εἰς 'οι' ἐπιρρήματα, ὅτε δηλοῖ τὴν ἐν τόπῳ ἢ τὴν εἰς τόπον σχέσιν, ὑπὲρ δύο συλλαβὰς ὄντα, περισπᾶται, Μεγαροῖ, Πυθοῖ, Φρεαροῖ, Παιανιοῖ, Ἁθμονοῖ, οὐδαμοῖ, μηδαμοῖ, πανταχοῖ, ἑκασταχοῖ, ἐνταυθοῖ, ὃ τὴν αὐτὴν ἔχει σημασίαν τῷ ἐνταῦθα τῷ πρωτοτύπῳ. τὰ δὲ δισύλλαβα τῶν εἰς 'οι' βαρύνεται καὶ περισπᾶται· περισπᾶται μέν, ὅτε ἔχει πρωτότυπον ὀξύτονον, παρὰ τὸ σφίγξ σφιγγοῖ, ἰσθμός ἰσθμοῖ, βυθός βυθοῖ, τὸ ἁρμοῖ συμπερισπᾶται τῷ ἁρμῷ. ἔστι δὲ τὸ ἁρμοῖ Συρακουσίων· ἁρμός γὰρ ἁρμοῦ ἁρμῷ καὶ συστολῇ ἁρμοῖ ὡς παρὰ Καλλιμάχῳ ἁρμοῖ πὰρ Δαναὸν γῆς ἀπὸ βουγενέων (fr. 230) ἁρμοῖ που κἀκείνῳ ἐπέτρεχε λεπτὸς ἴουλος (fr. 44). οὕτως Θέων ὁ Ἀρτεμιδώρου. τὰ δὲ ἀπὸ βαρυτόνων βαρύνεται, ἔξω ἔξοι, πέδον πέδοι »πέδοι δὲ βᾶσαι« Αἰσχύλος Προμηθεῖ δεσμώτῃ (v. 280), ἔνδον ἔνδοι »ἔνδοι Πραξινόα« ὁ Θεόκριτος (XV 1) οἶκος οἴκοι. Τὰ σχετλιαστικὰ τῶν εἰς 'οι' καὶ 'αι' ἄλογον ἔχει τὸν τόνον. ἃ μὲν γὰρ αὐτῶν περισπᾶται, ὡς τὸ ὀτοτοῖ ἔχον συμπαρακείμενον καὶ τὸ ἀταταῖ, καὶ τὸ οὐαῖ καὶ αἰαῖ, σαβοῖ τε καὶ αἰβοῖ καὶ τὸ σαβαῖ παρ´ Εὐπόλιδι ἐν Βάπταις. τὸ δὲ εὐαί παρὰ τῷ αὐτῷ ὀξύνεται »εὐαὶ σαβαῖ« ὡς τὸ αἴ, οὐαί, βαβαί. βαρύνεται δὲ τὸ οἴμοι ὤμοι. τὸ
On the one hand, it is reasonably derived from the barytone ὥρα, but it does not have a preposed element in -θεν. The adverbs in -οι, when they indicate relation in a place or motion to a place, if they are more than two syllables, take the circumflex: Μεγαροῖ, Πυθοῖ, Φρεαροῖ, Παιανιοῖ, Ἁθμονοῖ, οὐδαμοῖ, μηδαμοῖ, πανταχοῖ, ἑκασταχοῖ, ἐνταυθοῖ, which has the same meaning as the primitive ἐνταῦθα. But the disyllables among those in -οι are accented with the grave and with the circumflex: they take the circumflex, when they have an oxytone primitive, as from σφίγξ, σφιγγοῖ; ἰσθμός, ἰσθμοῖ; βυθός, βυθοῖ; and ἁρμοῖ is circumflexed together with ἁρμῷ. Now ἁρμοῖ is Syracusan; for ἁρμός, genitive ἁρμοῦ, dative ἁρμῷ, and by contraction ἁρμοῖ, as in Callimachus: ἁρμοῖ πὰρ Δαναὸν γῆς ἀπὸ βουγενέων (fr. 230); ἁρμοῖ που κἀκείνῳ ἐπέτρεχε λεπτὸς ἴουλος (fr. 44). Thus Theon son of Artemidorus. But those derived from barytones take the grave: ἔξω, ἔξοι; πέδον, πέδοι—“πέδοι δὲ βᾶσαι,” Aeschylus in Prometheus Bound (v. 280); ἔνδον, ἔνδοι—“ἔνδοι Πραξινόα,” Theocritus (XV 1); οἶκος, οἴκοι. The interjectional forms in -οι and -αι have an irrational accent. For some of them take the circumflex, such as ὀτοτοῖ, which has a corresponding form, and ἀταταῖ, and οὐαῖ and αἰαῖ, and also σαβοῖ and αἰβοῖ, and σαβαῖ in Eupolis’ Baptai. But εὐαί in the same author is accented with the acute—“εὐαὶ σαβαῖ”—like αἴ, οὐαί, βαβαί. But οἴμοι and ὤμοι take the grave. The