In Portuguese, it is relatively easy to turn simple statements into questions:

1.  For written forms, leave everything exactly as it is and merely add a question mark at the end of the sentence. When speaking, raise the intonation at the end of the sentence much like you would in English.

Sua mãe fala português +? = Sua mãe fala português?
Your mother speaks Portuguese +? = Your mother speaks Portuguese?

Ele é brasileiro +? = Ele é brasileiro?
He is Brazilian +? = He is Brazilian?

2.  Add one of the following phrases and a question mark at the end of the sentence:não? (no?); não é? (literally, not is?); não é verdade? (literally, "not is truth?"); não é assim? (literally, "not is so?"). These phrases are the Portuguese equivalents of such common English phrases as "isn't it?" "don't you?" "doesn't he/she/they?" "aren't you?" "isn't that so?," etc.

Sua mãe fala português, não é verdade?
Your mother speaks Portuguese, doesn't she?

Ele é brasileiro, não é assim?
He is Brazilian, isn't that so?