Personal Infinitive with "Sem

In English, we say "without them knowing." We use a pronoun ("them") and a gerund ("knowing"). In Portuguese, we do something much cooler. We take the infinitive and stick a tiny ending on it. This ending tells us exactly who the subject is. You don't even necessarily need to say "them" because the verb already screams it! This is particularly useful after prepositions like sem. It clears up confusion. If I say sem saber, am I the one who doesn't know? Is it you? Is it the guy across the street? Without the personal infinitive, we're all just guessing. With it, the sentence becomes crystal clear. It’s a bit like having a GPS for your verbs. Yes, even native speakers mess this up sometimes when they're in a rush, so don't feel bad if it takes a second to click. It's the difference between being a tourist and sounding like a local at a C1 level.

1. 1Creating these forms is surprisingly logical. You start with the basic infinitive (the form you find in the dictionary) and add specific endings. It’s like a Lego set for your mouth.
2. 2Start with the Infinitive (e.g., falar, comer, partir).
3. 3Add the Personal Endings:
4. 4eu: (no ending, same as the infinitive)
5. 5tu: add -es (falares)
6. 6ele/ela/você: (no ending, same as the infinitive)
7. 7nós: add -mos (falarmos)
8. 8vós: add -des (falardes) - mostly for old books or northern Portugal!
9. 9eles/elas/vocês: add -em (falarem)
10. 10Note that for eu and ele, the form is identical to the regular infinitive. You'll rely on context or a nearby pronoun to know who is who. It’s a simple system once you get the hang of it. Just remember: the verb stays in its "pure" form, and you just glue the tail on.

You should reach for this pattern whenever you use sem and the subject of the action is different from the main subject. This is the golden rule. Let's look at real-world scenarios.

• In a job interview: You might say, "I completed the project without them asking for help" (sem eles pedirem).
• Ordering food: "Can you bring the salad without us having to wait too long?" (sem nós termos que esperar).
• Travel: "He entered the country without the guards checking his passport" (sem os guardas verificarem).

Use it when you want to be specific. If the action of "not doing something" belongs to a specific person or group, give that verb its personal ending. It shows you have a high level of control over the language. It’s the "pro" way to handle transitions in a sentence. Think of it like putting the right stamp on an envelope; without it, the message might still arrive, but it looks a bit unfinished.

Don't get "ending happy"! If the subject of the whole sentence is the same as the subject of the infinitive, you usually stick to the Impersonal Infinitive (no endings).

For example: "I left without saying goodbye." In Portuguese, that's Saí sem dizer adeus. You don't need Saí sem eu dizer because we already know it was you! Adding the ending here sounds redundant and a bit clunky. It’s like wearing two hats at once. You only need the personal version when there’s a "subject shift." If the person doing the main action isn't the one doing the sem action, then you bring out the personal endings. Keep it simple when it’s just about you. Your listener will thank you for the brevity.

The most frequent trip-up is confusing the personal infinitive with the Future Subjunctive. They look identical for regular verbs!

Falar, falares, falar, falarmos, falarem are the same for both. The difference is the "trigger." The personal infinitive follows prepositions like sem, para, or até. The future subjunctive follows conjunctions like quando or se.

Another classic mistake is forgetting the -em for the third person plural. People often say sem eles falar when they should say sem eles falarem. It sounds a bit like saying "they goes" in English. It's understandable, but at C1, we want that extra polish. Also, be careful with the tu form. Even if you don't use tu often, knowing that -es ending is vital for comprehension. Don't let it catch you off guard like an unexpected rain shower in April!

How does this differ from the Subjunctive? Usually, after sem que, you must use the present or imperfect subjunctive.

• Sem eles saberem (Personal Infinitive) = "Without them knowing."
• Sem que eles saibam (Present Subjunctive) = "Without them knowing (literally: without that they know)."

Both mean the same thing, but the infinitive version is much more common in European Portuguese and sounds a bit more sophisticated in writing. The infinitive version is more direct. It’s the difference between taking the highway (infinitive) and the scenic route with more traffic lights (subjunctive). Another contrast is with the Gerund (-ndo). In Brazil, you might hear sem eles sabendo, but in standard formal Portuguese and in Portugal, the personal infinitive is the king of this structure.