Principal Parts of Common Verbs
Master the four principal parts rule and memorize 20 essential Latin verbs with irregular perfect stems, including fero, sum, eo, video, dico, capio, facio, and others critical for prose reading.
A lesson of Latin A2 — Elementary, in The Perfect System, about 10 minutes.
By the end of this lesson, you will have memorized the four principal parts of 20 essential Latin verbs — including the most common irregular verbs — and understand why irregular perfect stems must be learned, not derived.
Why Principal Parts Matter
The four principal parts of a Latin verb are non-negotiable:
- 1st sg. present active — the dictionary headword (amo)
- Present active infinitive — the conjugation class (amare)
- 1st sg. perfect active — gives you the perfect stem (amavi)
- Perfect passive participle (neuter nom. sg.) — gives you the passive perfect forms (amatum)
Without the 3rd and 4th parts, you cannot form the perfect system or translate passive constructions. Latin students who skip this memorization stall completely when they reach authentic prose.
Regular Perfect Stems: Four Patterns
Many Latin verbs form their perfect in predictable ways. Learning the pattern reduces the memorization burden.
| Pattern | Description | Example |
|---|---|---|
| -v- stem | Add -v- before -i: amavi | amo, amare, amavi, amatum |
| -u- stem | Add -u- before -i: monui | moneo, monere, monui, monitum |
| Reduplication | Repeat first consonant: cecini | cano, canere, cecini, cantum |
| Consonant stem | Ablaut or lengthening: duxi, dixi | duco, ducere, duxi, ductum |
The Core 20 Verbs — Four Principal Parts
Commit these to memory. They are the backbone of Latin prose.
| Verb | PP1 | PP2 | PP3 | PP4 | Meaning |
|---|---|---|---|---|---|
| amare | amo | amare | amavi | amatum | to love |
| monere | moneo | monere | monui | monitum |