Irregular Verbs
A handful of the most-used Latin verbs refuse to follow any of the four conjugations. Sum, possum, ferō, eō, fīō, volō, nōlō, mālō, edō, dō — together they account for a huge slice of every page of Caesar and Cicero.
They are old (athematic: endings glued straight onto the root, no thematic vowel) and have to be learned cold.
Each has its own quirk. Ferō drops the vowel in the present (fers, fert — not feris, ferit) and switches stems for the perfect (tulī, lātum). Eō contracts to a tiny one-syllable shell (eō, īs, it, īmus, ītis, eunt).
Fīō serves as the passive of faciō but wears 4th-conjugation clothes. The trap: their compounds inherit the irregularity — afferō, cōnferō, abeō, redeō, exeō, adsum, prōsum all decline like their parent verb.
Eight stems you cannot read Latin without — each athematic, each with its own quirk, each carrying its irregularity into every compound.
Compounds inherit: afferō, cōnferō, referō, abeō, redeō, exeō, adsum, prōsum, possum, cōnficiō — the prefix changes the meaning, never the conjugation.
| Case | Active Sg. | Active Pl. | Passive Sg. | Passive Pl. |
|---|---|---|---|---|
| Pres. 1 | ferō | ferimus | feror | ferimur |
| Pres. 2 | fers | fertis | ferris | feriminī |
| Pres. 3 | fert | ferunt | fertur | feruntur |
| Imperf. | ferēbam | — | ferēbar | — |
| Future | feram | — | ferar | — |
| Perf. | tulī | — | lātus sum | — |
| Imper. | fer | ferte | — | — |
| Case | Indic. | Subj. |
|---|---|---|
| Pres. 1 | eō | eam |
| Pres. 2 | īs | eās |
| Pres. 3 | it | eat |
| Pres. P.1 | īmus | eāmus |
| Pres. P.2 | ītis | eātis |
| Pres. P.3 | eunt | eant |
| Imperf. | ībam | īrem |
| Perf. | iī (īvī) | ierim |
| Pres. Part. | iēns, euntis | — |
See It In Action
— B. G. i. 26
Possum is the workhorse here: indicative potest/potuit, with infinitive posse — and almost always paired with a complementary infinitive (videre, ferre, ire). Notice the t→ss split: potuit but posse.
— B. G. v. 27
Deferunt, not deferiunt — ferō drops the thematic vowel and the compound dēferō inherits the irregularity. Whenever you see -ferō, -ferre, -tulī, -lātum, the parent verb's quirks carry over.
— B. G. i. 9
Two irregulars in one clause: ire (the bare 1-syllable infinitive of eō) governed by poterant (imperf. of possum). This pattern — modal possum + irregular infinitive — is everywhere in Caesar.
Students often try to conjugate afferō or abeō by their prefix's flavor. They don't — the base verb dictates everything.
compound of an irregular verb
conferunt, abīs, redeunt, attulī
they bring together / you go away / they go back / I brought to
wrongly regularized as 3rd or 4th conj.
conferiunt, abīvīs, redīvunt, attulvī
(none of these exist — but they look plausible)
Tip: Ask: what's the base verb under the prefix? con-fer-unt → ferō → use ferō's endings, never invented ones. Same trick for ad-, ab-, dē-, ex-, in-, ob-, prō-, re-, sub- + ferō / eō / sum / faciō.
In Caesar's Sequanis invitis ire non poterant, what form is poterant and what's it doing?
Study Tips
- •Drill sum and possum until you can rattle off all six tenses without thinking — they show up in every sentence and the subjunctive (sim, possim) carries half of all subordinate clauses.
- •For ferō, memorize fers, fert, ferte, fer (no -i-) and the perfect/supine stems tul- and lāt-. Once those are reflexes, every compound (affer-, confer-, refer-) is free.
- •Eō looks tiny but breaks like glass: iēns (gen. euntis) for the participle, itum for impersonal passives (itum est = "there was a going"). Read out loud — the rhythms stick.
- •When you see a compound verb, strip the prefix and ask whether the base verb is one of the irregulars. Conferō ≠ 3rd conjugation — contulī is the perfect, not cōnferī.