Meaning
To state a lack of knowledge or information.
Cultural Background
Brazilians often use 'Não sei não' to express suspicion. It's not just a lack of knowledge; it's a sign that something feels 'fishy'. In Portugal, 'Não sei' is often followed by 'de nada' (I don't know about anything) to emphasize a total lack of involvement in a situation. In Luanda, you might hear 'Não estou a ver', which literally means 'I'm not seeing', but is used idiomatically to mean 'I don't know' or 'I don't understand'. Politeness is key. 'Não sei' is often preceded by 'Desculpe' (Sorry) even if the person has no obligation to know the answer.
The Brazilian 'Não sei não'
If you want to sound like a local in Brazil, add a second 'não' at the end to show you are skeptical about something.
Saber vs Conhecer
Never use 'Não sei' for people. It's the most common mistake for English speakers!
Meaning
To state a lack of knowledge or information.
The Brazilian 'Não sei não'
If you want to sound like a local in Brazil, add a second 'não' at the end to show you are skeptical about something.
Saber vs Conhecer
Never use 'Não sei' for people. It's the most common mistake for English speakers!
Body Language
A slight shrug of the shoulders often accompanies 'Não sei' and makes you look much more natural.
Test Yourself
Fill in the blank with the correct form of the phrase.
Onde está o meu celular? Eu ____.
The subject is 'Eu' (I), so the verb 'saber' must be conjugated as 'sei'.
Which sentence is correct when talking about a person?
Você conhece o novo professor?
We use 'conhecer' for people, not 'saber'.
Complete the dialogue with the most natural informal response.
Amigo A: 'A que horas começa o filme?' Amigo B: '____, vamos ver no site.'
'Sei lá' is the most natural informal way to say 'I don't know' among friends.
Match the phrase to the situation.
A boss asking for a report you haven't finished.
In a formal work environment, a more professional variation is preferred over a blunt 'Não sei'.
🎉 Score: /4
Visual Learning Aids
Formality Levels of 'I don't know'
Practice Bank
4 exercisesOnde está o meu celular? Eu ____.
The subject is 'Eu' (I), so the verb 'saber' must be conjugated as 'sei'.
Você conhece o novo professor?
We use 'conhecer' for people, not 'saber'.
Amigo A: 'A que horas começa o filme?' Amigo B: '____, vamos ver no site.'
'Sei lá' is the most natural informal way to say 'I don't know' among friends.
A boss asking for a report you haven't finished.
In a formal work environment, a more professional variation is preferred over a blunt 'Não sei'.
🎉 Score: /4
Frequently Asked Questions
10 questionsNo, it's neutral. However, adding 'Desculpe' (Sorry) before it makes it more polite.
'Não sei' is neutral/standard. 'Sei lá' is informal and implies you don't care as much about the answer.
Yes, but it's more common to drop the 'Eu'. Adding 'Eu' adds a bit of emphasis on yourself.
Use 'Ainda não sei'.
Yes, it is universal across all Portuguese-speaking countries.
Use 'Não faço ideia'.
Yes, but in a formal email, 'Não possuo essa informação' or 'Desconheço' is better.
The second 'não' adds emphasis and often suggests doubt or suspicion.
Yes, it can stand alone as a full answer to a question.
It's a nasal vowel. Try to say 'ah' while closing your nose slightly.
Related Phrases
Sei lá
synonymI have no clue / Who knows
Não faço ideia
similarI have no idea
Não conheço
contrastI don't know (a person/place)
Quem sabe
builds onWho knows / Maybe
Não sei de nada
specialized formI know nothing about it
