The -g- Insertion Pattern

If you look at Italian's irregular verbs as a chaotic mess, you'll never finish memorizing them. But many of those "irregularities" are actually members of small patterns — and the -g- insertion pattern is one of the most rewarding to learn, because it accounts for several of the most-used verbs in the language all at once. Once you see the pattern, venire, tenere, rimanere, porre (and all its compounds), salire, valere stop being separate problems and become a single problem solved.

The pattern in one sentence

In the io and loro forms of certain irregular verbs, a -g- is inserted between the stem and the ending. The other four forms (tu, lui, noi, voi) preserve a more regular-looking stem — sometimes with another twist, sometimes without.

The -g- appears in the same two slots in every member of the family. It is the single most consistent shape in Italian's irregular system.

How the pattern sounds

The inserted -g- always sits before -o (in vengo, tengo, rimango, salgo, valgo, pongo and the corresponding loro forms). Because the vowel that follows is -o, the g is always hard — pronounced /g/ as in English "go," never the soft /dʒ/ of "gem." There is no spelling adjustment needed: c and g are automatically hard before -o.

The two flavors: with and without stem-vowel shift

The -g- pattern splits into two subgroups depending on whether the other (non-io, non-loro) forms also undergo a vowel change.

Flavor 1: -g- only (no extra change)

For some verbs, the irregularity is just the -g-. The other four forms keep the infinitive's stem unchanged.

Flavor 2: -g- plus an e → ie stem shift

For venire and tenere (and tenere's compounds — mantenere, ottenere, contenere, sostenere, intrattenere, appartenere), the -g- in io and loro is paired with a stem-vowel shift e → ie in the tu, lui, and 3sg-style stressed forms. The 1pl and 2pl don't shift because they aren't stressed on the root.

The connection between -g- insertion and stem-vowel shift is not random: it's the same pattern that appears in Latin descendants across Romance. Latin teneo, tenes, tenet > Italian tengo, tieni, tiene. The diphthongization e → ie happens under stress; the -g- comes from a separate phonological process. Both happen, and the pattern is closed — only this small set of verbs shows it.

For the full treatment of the e → ie shift in its own right, see the e → ie stem change.

The full family

Below is a working catalogue of the most useful -g- pattern verbs. Memorize this list and you have eliminated a dozen "irregularities" in one go.

The compounds of porre are especially numerous because porre itself is borrowed productively into prefixed forms across philosophical, legal, and scientific Italian. If you can conjugate pongo, you can conjugate the io form of all of them. The same goes for compounds of tenere — once tengo clicks, mantengo, sostengo, contengo, ottengo all work the same way.

Where the loro form trips up English speakers

The loro form of every -g- pattern verb stresses the root, exactly like every other Italian 3pl. So:

• vèngono, not vengòno
• tèngono, not tengòno
• rimàngono, not rimangòno
• sàlgono, not salgòno
• vàlgono, not valgòno
• pòngono, not pongòno

This rule is not a quirk of the -g- pattern — it's the universal Italian rule. But because the -g- gives the loro form a slightly more complex shape than usual, learners frequently slip and stress the penultimate syllable.

What the -g- pattern is NOT

It's worth distinguishing this irregularity from two other patterns that involve g but work differently.

Not the -h- insertion of -care/-gare verbs

Verbs like cercare and pagare insert a silent -h- before -e and -i endings (cerchi, paghiamo) to keep their c or g hard. That's a purely orthographic adjustment to the regular -are paradigm — the verb stays regular grammatically, just with a spelling fix. The -g- pattern, by contrast, is a real morphological irregularity: a consonant that doesn't exist in the infinitive shows up in two specific forms.

For the orthographic side, see spelling changes in conjugations.

Not the -lg-/-gli- alternation of -gliere verbs

Verbs ending in -gliere — scegliere (to choose), cogliere (to gather), togliere (to remove), raccogliere (to collect) — show a different alternation: -gli- in most forms, but -lg- in io and loro.

Notice: scelgo has -lg-, but scegli has -gli-. The -gliere verbs have their own internal logic. They're often grouped with the -g- pattern in textbooks because they share the io and loro slots, but the rest of the conjugation works differently.

Why the pattern exists

If you want the historical why: the -g- comes from Latin verb stems that ended in a velar consonant. Latin venio, venis, venit lost its /j/ in most forms but reinforced the velar in certain phonological environments. By the time we get to Old Italian, the result was a system in which a few verbs preserved a "hard" velar /g/ in exactly the io and loro slots, while losing it elsewhere. The pattern is closed — no new verbs join it — but it captures some of the most basic verbs in the language.

This explains why you cannot extend the pattern by analogy: you cannot conjugate, say, scrivere as scriggo. The -g- is a fossil from Latin, not a living productive rule.

Common mistakes

Key takeaways

The -g- insertion pattern is one of Italian's tightest, most useful irregularities to learn as a system rather than verb-by-verb.

Three points to internalize:

1. The -g- appears in exactly two forms: io and loro. The other four forms (tu, lui, noi, voi) do not take the -g-.

2. Two flavors of the pattern exist. "Just -g-" verbs (rimanere, salire, valere, porre and its compounds) keep the rest of the stem regular. "g- + e→ie" verbs (venire, tenere and its compounds) also shift the stressed root vowel from e to ie in tu, lui/lei, and the lui/lei-style imperative.

3. The loro form stresses the root. Vèngono, tèngono, rimàngono, sàlgono, vàlgono, pòngono — never the penultimate syllable.

To see this pattern in a single high-frequency verb in detail, study venire. For the e→ie shift on its own, see stem change e → ie. For the broader picture of irregularity types, spelling changes overview maps where each one fits.