Meaning
Expresses ignorance about the reason for something.
Cultural Background
Brazilians often add 'hein?' at the end for emphasis: 'Não sei por que, hein?'. It adds a layer of shared mystery. In Portugal, the phrase is often delivered with a more stoic expression. It can imply that some things are just 'destiny' (Fado). In Luanda, you might hear 'Não sei porquê' used as a filler phrase while someone is thinking of what to say next.
The Shrug
In Brazil, pair this phrase with a palms-up shrug for maximum native-like effect.
The Accent Rule
Remember: 'por que' (no accent) if words follow, 'porquê' (accent) if it's the end.
Meaning
Expresses ignorance about the reason for something.
The Shrug
In Brazil, pair this phrase with a palms-up shrug for maximum native-like effect.
The Accent Rule
Remember: 'por que' (no accent) if words follow, 'porquê' (accent) if it's the end.
Test Yourself
Fill in the blank with the correct form (por que or porquê).
Ela está brava, mas não sei ______.
Because it is at the end of the sentence, it needs the accent and is written as one word in some older grammars, but modernly 'porquê'.
Which sentence is correct?
Choose the most natural way to say 'I don't know why it's raining'.
'Saber' is for facts, and 'por que' (two words) is for the reason.
Complete the dialogue.
A: Por que você não ligou? B: ______.
'Não sei por que' is a valid, though slightly evasive, answer.
Match the phrase to the feeling.
When would you say 'Não sei por que'?
It expresses uncertainty or confusion.
🎉 Score: /4
Visual Learning Aids
Practice Bank
4 exercisesEla está brava, mas não sei ______.
Because it is at the end of the sentence, it needs the accent and is written as one word in some older grammars, but modernly 'porquê'.
Choose the most natural way to say 'I don't know why it's raining'.
'Saber' is for facts, and 'por que' (two words) is for the reason.
A: Por que você não ligou? B: ______.
'Não sei por que' is a valid, though slightly evasive, answer.
When would you say 'Não sei por que'?
It expresses uncertainty or confusion.
🎉 Score: /4
Frequently Asked Questions
3 questionsIn this phrase, it's always 'por que' (two words) because it's an indirect question. Use 'porque' (one word) only for giving answers.
Yes, 'Não sei' is shorter, but 'Não sei por que' is more specific to the reason.
That 'hat' is a circumflex accent. In Portuguese, the vowel 'e' becomes stressed and closed when it's at the end of a sentence followed by a punctuation mark.
Related Phrases
Sei lá
informal alternativeWho knows / I have no idea
Não faço ideia
synonymI have no idea
Por que será?
similarI wonder why?
