The Ω-Conjugation: Vowel Verbs, Contracting in the Present

316. Verbs in -άω, -έω, -όω contract the stem vowel -α-, -ε-, -ο- in the present system with the succeeding vowel, in accordance with §§ 29 and 30. (For paradigms see, §§ 313 – 315.)

a. Note also that -ι- in the second syllable is retained (on the line or subscript), and that -ο- with an ι-diphthong (-ει, -οι, -ῃ) gives -οι.

b. But, in the infinitive, -ειν (from -ε-εν, § 274) was no true diphthong (§ 27.a); hence -ά-ειν gives -ᾶν and ό-ειν gives -οῦν, without -ι-.

317. Outside of the present system the stem vowel -α-, -ε-, -ο- is lengthened (§ 28.a); -α- becomes -ᾱ- after -ε-, -ι-, or -ρ-, otherwise -η-.

θηράω (hunt), future θηρᾱ́σω, etc.
ῑ̓άομαι (heal), future ῑ̓ᾱ́σομαι, etc.
τῑμάω, (honor), future τιμήσω, etc.

a.χράομαι (use) and ἀκροάομαι (listen) are irregular.

318. In the paradigms (§§ 313 – 315) the uncontracted vowels are in parenthesis, the contract syllable follows next; for the uncontracted form read the parenthesis and omit the contract syllable, for the contract form omit the parenthesis.

319. In the present optative active the mode suffix -ιη- is more common in the singular, but rare elsewhere.

320. Seven verbs in -άω contract to -η instead of -ᾱ. The most frequent are ζάω (live), χράομαι (use), διψάω (thirst), πεινάω (hunger).

321. Monosyllabic stems in -ε contract only in the forms that give -ει. Thus πλε- (see § 257.b) (sail) makes πλεῖς, πλεῖ, ἔπλεις, ἔπλει, πλεῖν, but πλέω, πλέομεν, πλέῃς, πλέοιμι, etc.

a. δέω (bind) sometimes contracts throughout, but δέω (lack) and δέομαι (ask) follow the rule.

322. A few verb-stems in -α and -ε, with still fewer in -ο, do not lengthen that vowel in any system; some of these assume -σ- in the perfect middle or in the passive system or both.

The stem αἰνε- (approve) neither lengthens -ε- in Attic nor takes -σ-; two compounds, ἐπ-αινέω (praise) and παρ-αινέω (advise), are frequent. (But ᾔνημαι is found.)

a. In some verbs (as τελε-, end, cp. τὸ τέλος) the -σ- clearly belonged to the original stem, and has been lost except before -μ- and -τ-; others appear to have imitated these by inserting -σ- before -μ- and -τ-.

b. The perfect and pluperfect indicative middle have in the 3rd plural a compound form; the whole inflection (showing also the form of the participle) is as follows.

c. The future of τελέω (finish) and of καλέω (call) commonly drops -σ- and contracts, thus becoming like the present.

τελῶ, τελεῖς, τελεῖ, etc.

So also μαχοῦμαι for μαχέσομαι, from μάχομαι (μαχ-, μαχε-) fight, and ἐλῶ for ἐλάσω, from ἐλαύνω (ἐλα-) drive.