-IRE Verbs with -isc- in Italian

Overview

Most Italian verbs ending in -ire follow a regular conjugation pattern you may already know. However, a large group of -ire verbs insert -isc- between the stem and the ending in certain forms of the present tense. These are sometimes called "isc verbs" or "third conjugation verbs with -isc- infix."

The -isc- insertion happens in the singular forms (io, tu, lui/lei) and the third person plural (loro). The first and second person plural (noi, voi) remain regular. This pattern is not an exception — it is actually more common than the regular -ire pattern. Verbs like finire (to finish), capire (to understand), preferire (to prefer), and spedire (to send) all follow this pattern.

Understanding which -ire verbs take -isc- is essential at the A1 level because these verbs appear constantly in everyday Italian.

How It Works

Conjugation Pattern

Using finire (to finish) as the model verb:

Person	Pronoun	Regular -ire (dormire)	-isc- verb (finire)
1st singular	io	dormo	finisco
2nd singular	tu	dormi	finisci
3rd singular	lui/lei	dorme	finisce
1st plural	noi	dormiamo	finiamo
2nd plural	voi	dormite	finite
3rd plural	loro	dormono	finiscono

Notice that noi and voi forms are identical to regular -ire verbs. The -isc- infix only appears where the stress falls on the ending.

Common -isc- Verbs

Verb	Meaning	Example (io)
finire	to finish	finisco
capire	to understand	capisco
preferire	to prefer	preferisco
spedire	to send	spedisco
pulire	to clean	pulisco
costruire	to build	costruisco
guarire	to heal	guarisco
unire	to unite	unisco
colpire	to hit/strike	colpisco
suggerire	to suggest	suggerisco

Comparison with Regular -ire

The key difference lies in the singular and third person plural forms:

• Regular: io dormo, tu dormi, lui dorme, loro dormono
• -isc-: io finisco, tu finisci, lui finisce, loro finiscono
• Same: noi finiamo / dormiamo, voi finite / dormite

There is no reliable rule to determine which -ire verbs take -isc-. You must learn this as a property of each verb. However, most -ire verbs do take the -isc- infix — regular -ire verbs like dormire, partire, and sentire are actually the minority.

Examples in Context

Italian	English	Note
Finisco il lavoro alle cinque.	I finish work at five.	1st person singular with -isc-
Non capisco questa parola.	I don't understand this word.	Very common in daily speech
Lui preferisce il tè al caffè.	He prefers tea over coffee.	3rd person singular
Spedisci la lettera domani?	Are you sending the letter tomorrow?	2nd person singular
I bambini capiscono tutto.	The children understand everything.	3rd person plural -iscono
Noi puliamo la casa ogni sabato.	We clean the house every Saturday.	Noi form — no -isc-
Voi finite sempre tardi.	You always finish late.	Voi form — no -isc-
Preferisco restare a casa stasera.	I prefer to stay home tonight.	Common preference expression
Il dottore guarisce i pazienti.	The doctor heals the patients.	3rd person singular
Costruiscono un nuovo ponte.	They are building a new bridge.	3rd person plural
Non capisco, puoi ripetere?	I don't understand, can you repeat?	Useful classroom phrase
Suggerisco di partire presto.	I suggest leaving early.	Giving advice
Uniscono le due squadre.	They are joining the two teams.	3rd person plural

Common Mistakes

Forgetting -isc- in singular and 3rd plural

• Wrong: Io finio il libro.
• Right: Io finisco il libro.
• Why: Finire requires -isc- in the io, tu, lui/lei, and loro forms. Without it, the verb is incorrectly conjugated.

Adding -isc- to noi and voi forms

• Wrong: Noi finisciamo alle tre.
• Right: Noi finiamo alle tre.
• Why: The -isc- infix is never used with noi or voi. These forms follow the standard -ire pattern.

Using -isc- with regular -ire verbs

• Wrong: Io dormisco bene.
• Right: Io dormo bene.
• Why: Not all -ire verbs take -isc-. Dormire, partire, sentire, and aprire are regular -ire verbs.

Misspelling the -isc- forms

• Wrong: Tu capisci written as Tu capisci
• Right: Tu capisci
• Why: The spelling follows Italian phonetic rules: "sci" before e/i produces the "sh" sound. Pay attention to the exact letter patterns.

Confusing -isco and -esco

• Wrong: Io finesco.
• Right: Io finisco.
• Why: The infix is always -isc-, never -esc-. The vowel is always "i."

Practice Tips

1. Start by memorizing the six forms of finire as your anchor verb. Once you have the pattern, apply it to capire, preferire, and other -isc- verbs — the endings are always the same.
2. When you encounter a new -ire verb, check whether it takes -isc-. A good habit is to look up the "io" form: if it ends in -isco, all the other -isc- forms follow automatically.
3. Practice by creating sentences that contrast regular and -isc- verbs: "Io dormo e poi finisco il libro" — this reinforces which verbs use which pattern.

Related Concepts

• Prerequisite: Regular -IRE Verbs — the standard -ire conjugation you should know first
• Related: Regular -ARE Verbs — the most common Italian verb conjugation
• Related: Regular -ERE Verbs — the second conjugation pattern