One of the most important things to bear in mind when learning Portuguese is that there is a big difference between written Portguese, which is more formal and sticks to the grammar books, and oral Portuguese, which is a whole different story.
One place where this becomes apparent is the use of the word “não” in creating a negative sentence. Gramatically speaking, it is incorrect to place “não” at the end of the sentence; logistically, it is constantly placed at the end of the sentence in spoken Portuguese. Though technically, this structure is grammatically incorrect, it is frequently used this way in the oral form, usually in a response to a question.
Let’s take a look.
How it’s written: Não quero ir na festa. I don’t want to go to the party.
How it’s spoken: Quero ir na festa não. I don’t want to go to the party.
To be safe, stick to the grammar rules when writing, be it a term paper or a business email, but when spoken, it’s ok to speak like the Brazilians do.
Let’s look at a few more examples we’re likely to hear in spoken Portuguese.
Sei não, cara. I don’t know, man.
Podemos ir não. We can’t go.
Gosta não. She doesn’t like it.
Está triste não. He’s not sad.

airline yesterday, Azul Linhas Aéreas Brasileiras SA. The airline began flights from Salvador, Bahia; Campinas, São Paulo; and Porto Alegre, Rio Grande do Sul. Next month, two more cities will be added: Vitória, in Espirito Santo, and Curitiba, in Paraná. In 2009, twenty more cities will be added.
shows in Rio and São Paulo. She’s currently staying at the Copacabana Palace, where fans have gathered to try to catch a glimpse of the singer. Outside of Maracana Stadium, where the Rio shows will be held, fans are already camped out in anticipation of the first show on Sunday night. Brazilians have traveled from all over the country, spending thousands of reais to see the American pop star.