Eu não sei a razão.

I don't know the reason.

Breakdown of Eu não sei a razão.

• eu: I
• não: not
• saber: to know
• a razão: the reason

Questions & Answers about Eu não sei a razão.

Can I leave out Eu and just say Não sei a razão?

Yes. In European Portuguese you usually drop the subject pronoun when it’s clear from the verb form.

• Eu não sei a razão = Não sei a razão
• Both mean I don’t know the reason.
• Eu is only needed for emphasis or contrast, e.g. Eu não sei a razão, mas ela sabe (I don’t know the reason, but she does).

Why does não come before sei and not after it?

In Portuguese, não almost always comes directly before the conjugated verb.

• Correct: Eu não sei a razão.
• Incorrect: Eu sei não a razão.

For compound tenses with an auxiliary, não goes before the auxiliary:

• Eu não tenho sabido a razão. (very rare sentence, but structure is: não
  • tenho
    • sabido)

Why is it a razão and not just razão without the article?

Portuguese uses definite articles (o, a, os, as) more often than English.

• a razão = the reason (a specific, known reason)
• Bare razão (without an article) is possible but rarer here, and sounds more abstract or formulaic.

In this sentence, the speaker is clearly talking about a particular reason, so a razão sounds natural and idiomatic.

Why is it a razão and not o razão? Is razão feminine?

Yes, razão is a feminine noun, so it takes the feminine article a.

• a razão (the reason)
• uma razão (a reason)

If you look it up in a dictionary, it will appear as something like razão (f.), meaning feminine noun. There is no o razão.

Why is it sei and not something like sabo? How is saber conjugated?

Sei is the 1st person singular (eu) present tense form of the verb saber (to know – facts, information).

Saber is irregular in the present tense:

• eu sei – I know
• tu sabes – you know (informal singular)
• ele / ela / você sabe – he / she / you (formal) know
• nós sabemos – we know
• vocês sabem – you (plural) know
• eles / elas sabem – they know

So you must memorize eu sei, not eu sabo.

What’s the difference between saber and conhecer? Could I say Eu não conheço a razão?

Saber and conhecer both translate as to know, but they’re used differently:

• saber – knowing facts, information, how to do something
  
  • Eu não sei a razão. – I don’t know the reason.
  • Eu sei a resposta. – I know the answer.
• conhecer – being familiar with people, places, works, etc.
  
  • Eu conheço a Maria. – I know Maria.
  • Eu conheço Lisboa. – I know Lisbon / I’m familiar with Lisbon.

So Eu não conheço a razão sounds wrong; you need saber for this sentence.

Are there other common ways to say I don’t know the reason in European Portuguese?

Yes, some natural alternatives are:

• Não sei porquê. – I don’t know why.
• Não sei o motivo. – I don’t know the reason/motive.
• Não faço ideia. – I have no idea. (more informal)
• Não sei por que é que isso aconteceu. – I don’t know why that happened.

But Eu não sei a razão is clear and correct, just a bit more formal/literal.

How do you pronounce Eu não sei a razão in European Portuguese?

Approximate European Portuguese pronunciation (simplified):

• Eu – like “eh-oo”, often almost like “eu” in “euro”
• não – roughly “naung”, with a nasal vowel (like French “non” but with an a colour)
• sei – like English “say”
• a – like “uh” (a very short a)
• razão – roughly “ha-ZAUNG”:
  • initial r is a throaty sound (like French or German r)
  • z like English z
  • ão is a nasal sound, close to “aung” in “sung”, but with the lips more rounded

Spoken at natural speed, it links quite a bit: Eu não sei a razão.

Can I change the word order, like Eu sei não a razão or Eu não a sei razão?

No, those orders are ungrammatical.

• Standard order: Eu não sei a razão.
  • subject (Eu) – negation (não) – verb (sei) – object (a razão)

If you replace a razão with a pronoun, you might see:

• Eu não a sei. – I don’t know it.

But you don’t say Eu sei não a razão or Eu não sei razão in this context.

How would I say I didn’t know the reason in Portuguese? Is that very different?

You mainly use the past tenses of saber:

• Eu não sabia a razão. – I didn’t know the reason / I didn’t use to know the reason.
  
  • Imperfect tense (sabia): ongoing or background in the past.
• Eu não soube a razão. – I didn’t find out the reason / I never got to know the reason.
  
  • Simple past (soube): a completed event (learning or not learning at a specific moment).

So you choose between não sabia and não soube depending on the nuance you want.