Italian Subjunctive: The Congiuntivo and When to Use It

English nearly lost its subjunctive. It survives in fossils like if I were you and I insist that he be told, and most English speakers could not tell you what it is. Italian kept its own, the congiuntivo, and uses it every day, in ordinary conversation, after words as common as I think. That makes it the one piece of Italian grammar where English gives you less than nothing to go on. The consolation is that the forms are easy. The work is all in knowing when.

What the subjunctive is for

The indicative, the ordinary set of tenses, states things as facts. The subjunctive presents them as something else: an opinion, a wish, a fear, a possibility. Compare:

So che è vero. - I know it is true.

Penso che sia vero. - I think it is true.

Sapere states a fact, so the indicative è follows. Pensare states an opinion, so the subjunctive sia follows. Both sentences translate with the same English is, and that is precisely the problem: the distinction Italian makes is invisible in English, so you have to learn to feel it rather than translate it.

The subjunctive nearly always sits in a clause introduced by che, and it nearly always needs a trigger in the main clause. Learn the triggers and the mood mostly takes care of itself.

The present subjunctive endings

The regular forms reuse vowels you already know, with a twist: the -are verbs, whose present is full of a, take i, while the -ere and -ire verbs take a. The vowels swap sides.

Two things to notice. The noi form is identical to the present indicative, parliamo, so there is nothing new there at all. And the three singular persons are identical to each other, which has a practical consequence: in the subjunctive Italians often keep the subject pronoun they would normally drop, che io parli, che tu parli, because otherwise nobody knows who is speaking. It is the one place where the advice in Italian subject pronouns to leave them out gets reversed.

The irregulars mostly build themselves

Most irregular verbs form their present subjunctive from the io form of the present tense. Take off the -o and add the -ere endings:

Dovere bends the rule slightly (debba, though you will also see deva), but the trick holds for the rest, and it holds because the subjunctive grew out of the same stem. Five verbs genuinely have to be learned on their own, and they are, predictably, among the commonest in the language:

Sia is by some distance the subjunctive form you will say most often. If you can produce sia and abbia without hesitating, you can already cover a large share of real subjunctive use.

The triggers

Here is where the subjunctive is required, grouped by what the main clause is doing:

Some of these in action:

Credo che lui abbia ragione. - I believe he is right.

Spero che tu stia bene. - I hope you are well.

Voglio che tu venga. - I want you to come.

Bisogna che tu parli con lei. - You need to talk to her.

Esco senza che lui lo sappia. - I go out without him knowing.

And the opposite side, which matters just as much: certainty takes the indicative. So che, sono sicuro che, è chiaro che and è vero che all state facts, and are followed by the ordinary present. A useful test is to ask whether the speaker is presenting the second half as known. If yes, indicative. If it is believed, wanted, feared or merely possible, subjunctive.

Penso che: where Italian parts company with its neighbours

This is the point to underline twice. Spanish and French both use the indicative after an affirmative I think: creo que es verdad, je pense que c'est vrai. Italian does not. Penso che sia vero is standard Italian, and learners who arrive from Spanish or French carry the wrong habit straight across. An opinion, in Italian, is not a fact, and the grammar says so.

When the subject stays the same, use the infinitive

The subjunctive is for sentences with two different subjects. When the person thinking or wanting is the same person the second half is about, Italian drops che and uses an infinitive instead:

Voglio andare. - I want to go. (not voglio che io vada)

Penso di avere ragione. - I think I am right.

Wanting and preferring take a bare infinitive; opinion, hope and fear take di plus the infinitive: Spero di venire, Ho paura di essere in ritardo. This is not a stylistic preference. Voglio che io vada is simply wrong.

Relative clauses and superlatives

The subjunctive also turns up after che in a relative clause, when the thing described might not exist or is being picked out as extreme:

Cerco qualcuno che possa aiutarmi. - I'm looking for someone who can help me.

È il film migliore che io abbia mai visto. - It's the best film I have ever seen.

In the first, the speaker has not found that person yet. In the second, the superlative makes the claim a judgement rather than a plain fact. Neither is something to drill on day one, but you will meet both constantly, and recognising them saves you from reading them as mistakes.

The imperfect subjunctive, briefly

The present subjunctive has a past partner, and you have met it already in the conditional: it is the form after se in an unreal if sentence. It is regular to the point of dullness. Take the infinitive, drop the -re, add -ssi, -ssi, -sse, -ssimo, -ste, -ssero: parlassi, parlasse, parlassimo, parlaste, parlassero.

Essere is the exception worth knowing, fossi, fosse, fossimo, foste, fossero, fare and dire bring back their long Latin stems (facessi, dicessi), and dare and stare switch their a to e (dessi, stessi). The imperfect subjunctive also follows a main verb in the conditional or the past:

Vorrei che tu venissi. - I would like you to come.

Phrases worth learning whole

A few subjunctive expressions are so frequent that they are better learned as vocabulary than analysed:

Che io sappia. - As far as I know.

Qualunque cosa succeda. - Whatever happens.

Magari fosse vero! - If only it were true!

Prima che sia troppo tardi. - Before it is too late.

Is the congiuntivo dying?

You will read that it is. Italian newspapers have been announcing the death of the congiuntivo for decades, and in relaxed speech you will certainly hear penso che è in place of penso che sia. But many linguists think the claim is overstated: the congiuntivo is receding in some casual contexts, not disappearing. Educated speech, broadcasting and nearly all writing still use it, and Italians are quick to notice when it goes missing: dropping it is one of the things that mark a speaker as careless, in the same way that between you and I grates on some English ears. A learner has no reason to copy the casual version. Use the subjunctive and nobody will ever think less of you for it; leave it out and some people will.

Mistakes English speakers make

The indicative after penso che. The biggest one, and the most audible. Opinion takes the subjunctive: penso che sia, credo che abbia.

The subjunctive when the subject is the same. Voglio che io vada is not Italian. Same subject, infinitive: Voglio andare.

The subjunctive after certainty. Once learners discover the subjunctive, some start using it everywhere. So che è vero: knowing is not an opinion.

Mixing up the -are and -ere endings. The vowels swap: -are verbs take -i (che tu parli), -ere and -ire verbs take -a (che tu creda). Using the -a with an -are verb produces something that sounds like the wrong verb entirely.

Dropping the pronoun where it is needed. Che parli could be I, you, he or she. Put the pronoun back when the context does not already make it clear.

What to practise

Learn sia, abbia, stia and sappia first, then the io-form trick for the rest. Next, drill the triggers in pairs, a fact against an opinion: So che è against Penso che sia, until the contrast feels like a difference in meaning rather than a rule you are applying. Then practise the same-subject switch, Voglio andare against Voglio che tu venga. From here, the Italian imperative is the natural next step, because the polite command form is borrowed straight from the subjunctive, and the Italian course drills both on real sentences.