Formal and Literary Personal Infinitive Usage

In most languages, the infinitive is "impersonal." It does not change based on the person. In English, "to eat" is always "to eat." But Portuguese allows the infinitive to conjugate. This means the verb changes to match the subject. It looks like a hybrid between a basic verb and a conjugated one. You are giving the infinitive a clear identity. This usually happens when the verb follows a preposition. It is a way to avoid ambiguity. If you have two different people in one sentence, this is your best friend. It acts like a grammar traffic light. It tells the reader exactly who is moving and when.

1. 1Creating the personal infinitive is surprisingly easy. You take the regular infinitive of any verb. Then, you simply add specific endings to the end of it. It works the same for -ar, -er, and -ir verbs. Most irregular verbs also follow this pattern perfectly. Here is how you build it:
2. 2For eu, do not add anything. It stays as the base form.
3. 3For tu, add the ending -es to the verb.
4. 4For você/ele/ela, do not add anything. It is identical to eu.
5. 5For nós, add the ending -mos to the verb.
6. 6For vós, add the ending -des. This is for very formal texts.
7. 7For vocês/eles/elas, add the ending -em to the verb.
8. 8Yes, it really is that simple. It is like a rare moment of peace in a world of irregular verbs.

The most common time to use it is after prepositions. Words like para, por, sem, até, and com. You must use it when the subject of the infinitive is different. Imagine you are at a job interview. You might say, "I brought these files for you to read." In Portuguese, that is Trouxe estes arquivos para vocês lerem. The -em on lerem tells us the interviewers are the ones reading. It is also common after phrases like antes de and depois de. In formal writing, it adds a layer of elegance. It prevents your sentences from becoming cluttered with the word que. Use it when you want to sound sophisticated and clear.

Do not use the personal infinitive after modal verbs. These are verbs like dever, poder, querer, and costumar. If you say "We should speak," it is Devemos falar. You do not conjugate the second verb. Saying Devemos falarmos is a big mistake. It is like wearing two belts at the same time. Also, avoid it if the subject of both verbs is the same. "I want to sleep" is just Quero dormir. Adding an ending there is unnecessary and sounds clunky. It is like bringing a heavy suitcase for a five-minute walk. Keep it simple when the subject is obvious.

The biggest trap is the future subjunctive. For regular verbs, they look exactly the same. Se eu falar (Future Subjunctive) versus Para eu falar (Personal Infinitive). The trick is to look at the "trigger" word. If you see se or quando, it is almost always the subjunctive. If you see a preposition like para, it is the personal infinitive. Another mistake is forgetting the plural ending. Many students say para eles falar instead of para eles falarem. This sounds very "broken" to a native ear. Finally, watch out for the tu form. The -es ending is small but very important for accuracy.

How does this differ from using a full clause? You could say para que vocês leiam (using the subjunctive). Or you could say para vocês lerem (using the personal infinitive). The personal infinitive is often more direct. It feels more modern and punchy in professional writing. Compared to the impersonal infinitive, the personal one is about clarity. If there is any doubt about who is acting, go personal. If the action is general or the subject is the same, stay impersonal. It is a choice between being vague and being surgical. Choose the surgical approach for your C1 exams.