Rules for forming and spelling adjectives in -ιος (use of diphthong ει), accentuation patterns (proparoxytone, preparoxytone) in presents and futures, dialectal t→s shifts (Laconian), examples (ἀστεῖος, Βακχεῖος, ὀρθῶσιος, φυλάξιος, πλησίος, ἐνιαύσιος).
γράφεσθαι. ὅσα γὰρ μὴ μονογενῆ πρὸ μιᾶς ἔχουσι τὸν τόνον καὶ ἐν τῇ τρίτῃ τὸ 'α' καὶ δύο σύμφωνα ἢ κατ´ ἐπιπλοκὴν ἢ κατὰ διάστασιν, διὰ τῆς 'ει' διφθόγγου γράφεται, ἀστεῖος, Καδμεῖος, ἀνδρεῖος, Ἀργεῖος, Βακχεῖος. πρόσκειται «μὴ μονογενῆ» διὰ τὸ Βάκχιος κύριον. τὸ δὲ ἀντίος σεσημείωται. ἐξηκολούθησε δὲ κατὰ τὴν γραφὴν τοῖς εἰς 'ιος' ἀπὸ ἐνεστώτων γινομένοις. Ἔτι καὶ τὰ εἰς 'ιος' ἀπὸ μέλλοντος γινόμενα προπαροξύνεται, ὀρθώσομαι ὀρθώσιος, ἀσπάσομαι ἀσπάσιος, φυλάξομαι φυλάξιος, ἀλέξω ἀλέξιος, κτήσω κτήσιος, μνήσω μνήσιος, αἰνήσω Αἰνήσιος, ἀρκέσω Ἀρκέσιος καὶ πλεονασμῷ τοῦ 'ι' Ἀρκείσιος, ἄρσω ἄρσιος καὶ ἀνάρσιος, ἄξω ἄξιος, θαυμάζω θαυμάσιος. ἅζω τὸ σέβομαι ἅσιος καὶ τροπῇ τοῦ 'α' εἰς 'ο' ὅσιος. ὀξύνεται δὲ τὸ δέξομαι δεξιός καὶ ἕψομαι ἀνεψιός. τοῦ δὲ πλησίος ἀπὸ τοῦ πλητός ἔχομεν τὴν χρῆσιν· ὁ γὰρ ἄπλητος ὁ ἀπροσπέλαστος, πλητός πλησίος ὡς ἄμβροτος ἀμβρόσιος τροπῇ τοῦ τέλους. οὐ γέγονε δὲ τὸ πλησίος παρὰ μέλλοντα. οἱ γὰρ Λάκωνες τὰ παρὰ μέλλοντα εἰς 'τ' οὐ τρέπουσιν, ἀλλὰ ἀπὸ τοῦ 'τ' εἰς τὸ 'σ'· ἐνιαυτός ἐνιαύσιος ἐνιαύτιος λέγουσιν ὑπόμνησιν διδόντες τοῦ προτέρου 'τ'· πλοῦτος πλούσιος πλούτιος. τὸ δὲ πλησίος πλατίος λέγουσιν, ὥστε οὐ παρὰ μέλλοντα. παρὰ τὸ πέλω παραγωγὸν πελάζω τὸ προσεγγίζω, ῥηματικὸν ὄνομα πλατός καὶ πλητός καὶ κατὰ τροπὴν τοῦ 'τ' εἰς 'σ' καὶ κατὰ παραγωγὴν πλησίος ὡς ἄμβροτος ἀμβρόσιος. Πλήσιος δὲ κύριον ὄνομα ἀνδρὸς ἱεροῦ προπαροξύνεται.
To be written. For whatever are not monogenic have the accent before the penult and, in the third syllable, an α and two consonants, either in combination or in separation, are written with the diphthong ει: ἀστεῖος, Καδμεῖος, ἀνδρεῖος, Ἀργεῖος, Βακχεῖος. The proviso “not monogenic” is added because of the proper name Βάκχιος. But ἀντίος has been marked as exceptional. It followed, in its spelling, those in -ιος formed from present stems. Further, those in -ιος formed from a future are accented on the antepenult: ὀρθώσομαι ὀρθώσιος, ἀσπάσομαι ἀσπάσιος, φυλάξομαι φυλάξιος, ἀλέξω ἀλέξιος, κτήσω κτήσιος, μνήσω μνήσιος, αἰνήσω Αἰνήσιος, ἀρκέσω Ἀρκέσιος and, with addition of ι, Ἀρκείσιος, ἄρσω ἄρσιος and ἀνάρσιος, ἄξω ἄξιος, θαυμάζω θαυμάσιος. ἅζω, meaning “I revere,” gives ἅσιος, and by change of α to ο, ὅσιος. But δέξομαι gives δεξιός with acute accent, and ἕψομαι gives ἀνεψιός. As for πλησίος, from πλητός we have the usage: for ἄπλητος means “inaccessible,” and πλητός gives πλησίος, as ἄμβροτος gives ἀμβρόσιος, by change of the ending. But πλησίος has not been formed from a future; for the Laconians do not change the forms from a future into τ, but from τ into σ: they say ἐνιαυτός ἐνιαύσιος ἐνιαύτιος, giving a reminder of the earlier τ; and πλοῦτος, πλούσιος, πλούτιος. But they say πλατίος for πλησίος, so that it is not from a future. From πέλω, with the derivative πελάζω “I bring near,” comes the verbal noun πλατός and πλητός, and by change of τ to σ and by derivation, πλησίος, as ἄμβροτος, ἀμβρόσιος. Πλήσιος, however, a proper name of a sacred man, is accented on the antepenult.