According to the ending of the verb-stem, ω-verbs are termed:
1. Vowel (or pure) verbs:
a. Not contracted: those that end in υ or ι, as λῡ́-ωloose, παιδεύ-ωeducate, χρῑ́-ωanoint. Such verbs retain the final vowel of the stem unchanged in all their forms.
b. Contracted: those that end in α, ε, ο, as τῑμῶhonour from τῑμά-ω, ποιῶmake from ποιέ-ω, δηλῶmanifest from δηλό-ω.
2. Consonant verbs, as:
Liquid or nasal verbs: δέρ-ωflay, μέν-ωremain.
Verbs ending in a stop (or mute), as ἄγ-ωlead, πείθ-ωpersuade.
N.—Verbs ending in a stop consonant are called labial, dental, or palatal verbs. Consonant verbs do not retain the final consonant of the stem unchanged in all their forms. The final consonant may be assimilated to a following consonant, or may form with it a double consonant.
§§405–407PERFECT AND PLUPERFECT MIDDLE (AND PASSIVE)
§409 cEXPLANATION OF THE PERFECT AND PLUPERFECT FORMS
Euphonic Changes.—For the euphonic changes in these forms see 82-87, 103.
a. Labial Stems.—λέλειμ-μαι is for λελειπ-μαι, λέλειφ-θον is for λελειπ-σθον, λέλειφθε is for λελειπ-σθε (103). In the same manner are inflected other labial stems, as τρῑ́βω (τρῑβ-) rub, ῥῑ́πτω (ῥῑπ-) throw:τέτρῑμ-μαι for τετρῑβ-μαι, τέτρῑψαι for τετρῑβ-σαι, etc. Stems ending in μπ drop π before μ, but retain it before other consonants. Thus,
b. Dental Stems.—πέπεισ-ται is for πεπειθ-ται (83), πέπεισ-θον is for πεπειθθον (83), πέπεισθε is for πεπειθ-(σ)θε (83, 103). The ς thus produced was trans ferred to the first persons πέπεισμαι, πεπείσμεθα (86, 87). Like πέπεισμαι, etc., are formed and inflected ἔψευσμαι from ψεύδω (ψευδ-) deceive, πέφρασμαι from φράζω (φραδ-) declare, ἔσπεισμαι (100) from σπένδω (σπενδ-) pour a libation.
§§513–516II. PRESENTS IN -ττω (IONIC AND LATER ATTIC -σσω, 78)
Stop Verbs.—Labial (π, β, φ) and palatal (κ, γ, χ) stops at the end of the verb-stem unite with ς to form ψ or ξ. Dentals (τ, δ, θ) are lost before ς (98).
a. When ε or ο is added to the verb-stem, it is lengthened to η or ω: as βούλομαι (βουλ-ε-) wishβουλήσομαι, ἁλίσκομαι (ἁλ-ο-) am capturedἁλώσομαι. So also in the first aorist and in other tenses where lengthening is regular.
Stop Verbs.—Labial (π, β, φ) and palatal (κ, γ, χ) stops at the end of the verb-stem unite with ς to form ψ or ξ. Dentals (τ, δ, θ) are lost before ς (cp. 98).