Regular vs Irregular Verbs

A regular Italian verb is one whose stem stays put and whose endings follow the standard pattern of its conjugation class. Once you know that parlare takes the regular -are endings, you can predict every one of its 95-plus inflected forms with no extra information. An irregular verb breaks the pattern somewhere — either by changing its stem in a particular tense, or by taking endings that do not match its class. The good news is that irregularity in Italian is rarely total. Most so-called "irregular" verbs are perfectly regular in seven or eight tenses out of fourteen, with the irregularity concentrated in just one or two corners of the paradigm.

This page tells you where the irregularities live, why they live there, and which families of patterns you will meet again and again.

What "regular" means in Italian

A regular Italian verb does three things consistently:

1. The stem (what you get by removing -are, -ere, or -ire from the infinitive) stays the same in every form. Parlare → parl- → parlo, parlavo, parlerò, parlassi, parlato.
2. The endings match the standard table for that conjugation class.
3. The stress falls in the predictable places (penultimate in most forms; antepenultimate in the third-person plural of the present and the entire passato remoto).

If a verb does any of these three things differently in even one tense, it is technically irregular — but the irregularity may be confined to a single mood or tense and follow a recognisable pattern.

How the three classes differ in regularity

The three conjugation classes do not behave equally when it comes to irregularity.

The -are class is almost all regular

Of the thousands of -are verbs, only four are seriously irregular: andare (to go), dare (to give), stare (to stay/be), and fare (to do/make). Fare looks like an -are verb but is actually a contraction of the Latin facere, which is why its conjugation is closer to that of an -ere verb (facevo, fatto, facemmo). Every other -are verb you will meet — parlare, mangiare, lavorare, comprare, abitare, ascoltare, guardare, studiare, cantare — is regular.

The -ere class is where the irregularities cluster

The -ere class inherited Latin's most chaotic conjugations, and many of its verbs show irregularity in two specific places: the passato remoto and the participio passato. Take prendere — perfectly regular in the present (prendo, prendi, prende, prendiamo, prendete, prendono), the imperfect (prendevo), and the future (prenderò) — but it suddenly becomes presi, prendesti, prese... in the passato remoto, with the participle preso.

This is the pattern to expect with most -ere verbs: you can predict the present, the imperfect, the future, and the conditional from the infinitive, but you have to learn the passato remoto stem and the past participle separately. We will see why below.

The -ire class splits in two

-ire verbs come in two flavours, and which flavour a verb belongs to is essentially unpredictable from the infinitive — you have to learn it.

The pure -ire group conjugates with no extra material: dormire → dormo, dormi, dorme, dormiamo, dormite, dormono. About fifty everyday verbs follow this pattern, including partire, sentire, aprire, offrire, seguire, vestire, soffrire, servire.

The -isco group inserts -isc- between the stem and the ending in three forms of the present singular and the third-person plural: finire → finisco, finisci, finisce, finiamo, finite, finiscono. Around 500 verbs follow this pattern, including capire, preferire, pulire, costruire, spedire, suggerire.

The split is purely a present-tense phenomenon: in every other tense, finire and dormire take exactly the same endings. We treat the -isco insertion in detail in Regular -ire Verbs with -isco.

Irregularity is usually local, not global

Here is the most useful insight in this whole topic: very few Italian verbs are irregular everywhere. The two famous exceptions are essere and avere, which are irregular in nearly every tense. But for most other "irregular" verbs, the irregularity is confined to one or two specific places in the paradigm. Once you know where to look, the system becomes much more manageable.

The lesson: when you encounter a new "irregular" verb, the question is not is it irregular but where exactly is it irregular. Often it is just the participle and the passato remoto — easy enough to memorise as two extra pieces of information attached to a regular verb.

The three families of irregular passato remoto

Most of the irregularity in the -ere class lives in the passato remoto (the literary/southern past tense — see Passato Remoto Overview). The good news is that these irregularities fall into three big families. Once you can recognise the family, the verb is no longer mysterious.

Family 1: the -si stem

The largest family. The first-person singular ends in -si, and the third-person singular ends in -se. The middle persons (tu, noi, voi) keep the regular stem and endings.

The pattern is so consistent that if you encounter a new -ere verb whose participle ends in -so or -sso, you can confidently predict that its passato remoto belongs to this family.

Family 2: the double-consonant stem

A smaller but very common family. The 1sg, 3sg, and 3pl take a stem with a doubled consonant.

Notice that in this family the past participles tend to be regular (bevuto, caduto, saputo, tenuto, voluto, venuto — all in -uto). It is the passato remoto stem that is doing the irregular work.

Family 3: the -cqu- pattern

A small but historically important family. The 1sg, 3sg, and 3pl insert -cqu- into the stem.

The -cqu- comes from Latin perfect stems in -cu- (where the u was a consonantal /w/), which geminated and produced /kkw/ in Italian: placuit → piacque, tacuit → tacque. Nacque was later remodeled on the same template even though Latin nasci had a different perfect (natus sum). This family is small but extremely common because nascere and piacere are essential vocabulary.

Why the participle is often irregular

In the -ere class, an irregular passato remoto almost always comes with an irregular past participle, and there is a reason: both forms inherit directly from the Latin perfect stem, which was different from the present stem. Scribere had a perfect scripsi and a participle scriptum — and in Italian these became scrissi and scritto. The present stem stayed close to Latin (scrivo ← scribo), but the perfect-system forms went their own way over a thousand years ago.

This is why memorising the participle and the 1sg passato remoto together is so efficient: they come from the same historical root.

How English and Italian compare on irregularity

English and Italian have similar amounts of verb irregularity, but it lives in different places. English concentrates its irregularity in the simple past and the past participle (go/went/gone, write/wrote/written, take/took/taken). Everything else (present, future, gerund) is built from the infinitive without surprises.

Italian likewise concentrates irregularity in the passato remoto and the participio passato — strikingly similar to English's pair. The big difference is that Italian also has irregularities in the future and conditional (vedrò not vederò; andrò not anderò) and in scattered present-tense forms (the so-called "g-pattern" verbs like vengo, tengo, salgo, scelgo).

Where to find per-verb tables

This page maps the territory; for the actual paradigms of individual verbs, see the verb reference pages — each major verb has its own complete conjugation table. For systematic treatments of the irregular passato remoto families, see Passato Remoto: -si Pattern and Passato Remoto: Double Consonant Pattern. For irregular participles, see Irregular Past Participles.

Common mistakes

Key takeaways

• A regular verb keeps its stem and follows its class endings; an irregular verb breaks the pattern somewhere.
• -are verbs are nearly all regular (only andare, dare, stare, fare are seriously irregular).
• -ere verbs are the most irregular class, with the passato remoto and the participle being the usual trouble spots.
• -ire verbs split into pure (dormire) and -isco (finire) — the split affects only the present tense.
• Three families cover most irregular passato remoto verbs: the -si stem (presi), the double-consonant stem (bevvi, caddi), and the -cqu- pattern (nacqui, piacqui).
• For any irregular verb, learning four forms — 1sg present, future stem, 1sg passato remoto, past participle — gives you nearly the whole paradigm.