In short

The present subjunctive (presente do conjuntivo) is the mood Portuguese uses for wishes, doubts, and things that are wanted rather than stated as fact - you will drill where it is required in the next lesson. This lesson teaches you to build it, and it is mechanical: take the eu-form of the present indicative (Lessons 6-8), drop the -o, and add the “opposite” set of endings. Learn it once and you get two more tools for free, because the negative imperative (não fales) and the formal / plural imperative (fale, falem) are simply the subjunctive in disguise. So a single paradigm powers your commands, your requests, and every subjunctive you will meet from here on.

The rule

Building it from the eu-form

The recipe never changes:

1. Take the 1st-person singular of the present indicative - the eu form.
2. Drop the final -o.
3. Add the endings that “swap conjugation”: -ar verbs take e-endings, -er / -ir verbs take a-endings.

• falar -> falo -> fal- -> fale, fales, fale, falemos, faleis, falem.
• comer -> como -> com- -> coma, comas, coma, comamos, comais, comam.
• partir -> parto -> part- -> parta, partas, parta, partamos, partais, partam.

The huge payoff of the eu-form rule: any irregularity in the eu-form is carried straight into the subjunctive. If you know tenho, faço, digo, posso, venho, ponho, vejo, trago, saio, ouço, peço, perco, you already know the subjunctive stems:

Spelling changes that protect the sound

When the swapped ending would change how the stem sounds, the spelling adjusts to keep the original consonant sound (recall the hard/soft spelling reflexes from the reading & pronunciation guide):

• -car -> -que: ficar -> fique, tocar -> toque.
• -gar -> -gue: chegar -> chegue, pagar -> pague.
• -çar -> -ce: começar -> comece, almoçar -> almoce.
• -cer -> -ça: conhecer -> conheça, parecer -> pareça.
• -ger / -gir -> -ja: proteger -> proteja, dirigir -> dirija.
• -guir -> -ga: seguir -> siga, conseguir -> consiga.

These are not new irregulars - the sound is identical, only the letter changes to hold it.

The genuinely irregular subjunctives

A short list does not come from the eu-form and must be memorised. There are only seven common ones:

The negative and formal imperative come from the subjunctive

Here is why this lesson bundles the imperative. In Lesson 19 you learned the affirmative tu command, which is special (fala!, come!, parte!). Everything else in the command system is just the present subjunctive:

• Negative commands, all persons: não fales (tu), não fale (você), não falem (vocês). Even tu, whose affirmative is irregular, uses the subjunctive when negated.
• Affirmative commands to você / o senhor / vocês, and “let’s”: (o senhor) fale, (vocês) falem, (nós) falemos (“let’s speak”).

So the only command form that is not the subjunctive is the bare affirmative tu (and the archaic vós falai). Learn the subjunctive and your polite requests, your prohibitions, and your “let’s…” are all done.

Forms & patterns

Regular present subjunctive endings:

The command system for falar, showing where the subjunctive takes over:

Examples

Common mistakes

• Building the subjunctive from the infinitive stem -> build it from the eu-form: ter gives tenho -> tenha, never ter- -> teia.
• ficar -> fice -> fique - keep the hard k sound: -car -> -que, -gar -> -gue, -çar -> -ce.
• não fala tão alto -> não fales tão alto - the negative tu command uses the subjunctive, even though the affirmative tu (fala!) does not.
• Using the indicative for a polite command: Fecha a porta to a stranger -> Feche a porta - the você / o senhor command is the subjunctive.
• que ele vai after espero que -> que ele vá - ir has a fully irregular subjunctive (vá, vás, vá…); do not reuse the indicative.
• sejamos, sejais, sejam misapplied to estar -> esteja, estejamos, estejam - ser and estar have separate irregular subjunctives; keep them apart.
• dê written de -> dê - the dar subjunctive carries a circumflex to mark the closed vowel and separate it from the preposition de.

Tips

• Chant the recipe: “eu-form, drop the -o, swap the vowel.” It converts almost every verb, regular or irregular, in one step.
• The spelling changes (-que, -gue, -ce, -ça, -ja, -ga) are sound-preservers, not exceptions - say the word aloud and you will hear that nothing changed.
• Memorise the seven true irregulars as a block: seja, esteja, vá, haja, saiba, dê, queira - they cover a huge share of real speech.
• Think of the imperative as “subjunctive minus tu-affirmative”: once the subjunctive is automatic, every prohibition (não faças) and every polite command (faça, façam) falls out for free.
• The nós subjunctive doubles as “let’s…”: Vamos! aside, façamos, comecemos, saiamos all mean “let’s do / start / leave”.
• In Brazil, because você is the default “you”, the everyday command is usually this subjunctive form (fala heard in speech is colloquial); the European tu affirmative (fala! vs não fales) split is sharper in EP - see Lesson 10.