[829.] (1.) The present stem of many verbs in -ere is formed by adding a variable vowel -o|e-, which appears in the first person singular active as , to a root ending in a consonant or in two consonants: as,

Present Stem.Verb.From Theme.
rego|e-regō, guidereg-
verto|e-vertō, turnvert-

Other examples are: tegō, cover, petō, make for; mergō, dip, serpō, creep; pendō, weigh; dīcō, say, fīdō, trust, scrībō, write, with long ī for ei ([98]); dūcō, lead, with long ū for eu, ou ([100]); lūdō, play, with long ū for oi, oe ([99]); laedō, hit, claudō, shut; rādō, scrape, cēdō, move along, fīgō, fix, rōdō, gnaw, glūbō, peel. *furō, rave; agō, drive, alō, nurture. gignō, beget, (gen-, gn-), has reduplication, and sīdō, settle, light (sed-, sd-), is also the result of an ancient reduplication ([189]).

[830.] In some present stems an original consonant has been modified: as, gerō, carry (ges-), ūrō, burn ([154]); trahō, draw (tragh-), vehō, cart ([152]); or has disappeared: as, fluō, flow (flūgu-).

[831.] Some roots in a mute have a nasal before the mute in the present stem: as, frangō, break (frag-). Other examples are: iungō, join, linquō, leave, pangō, fix, pingō, paint; findō, cleave, fundō, pour; -cumbō, lie, lambō, lick, rumpō, break ([164, 3]). The nasal sometimes runs over into the perfect or perfect participle, or both.

[832.] (2.) The present stem of many verbs in -ere is formed by adding a suffix ending in a variable vowel -o|e-, which appears in the first person singular active as , to a root: thus, -nō, -scō, -tō, -iō: as,

Present Stem.Verb.From Theme.
lino|e-linō, besmearli-
crēsco|e-crēscō, growcrē-
pecto|e-pectō, combpec-
capio|e-capiō, takecap-

[833.] (a.) -nō is added to roots in a vowel, or in a continuous sound, -m-, -r-, or -l-.

So regularly linō, besmear, sinō, let; temnō, scorn, cernō, sift, spernō, spurn, only. The third persons plural danunt (Naev., Plaut.) for dant, prōdīnunt, redīnunt (Enn.) for prōdeunt, redeunt hardly belong here; their formation is obscure. In a few verbs, -n is assimilated ([166, 6]): as, tollō, lift. Sometimes the doubled l runs into the perfect ([855]): as, vellī, fefellī. minuō, lessen, and sternuō, sneeze, have a longer suffix -nuo|e-.

[834.] (b.) -scō, usually meaning ‘begin to,’ forms presents called Inceptives or Inchoatives.