The Portuguese alphabet is a Latin alphabet with 26 letters. Also, the language uses accent marks to show sound changes and stressed syllables. The accents used in Portuguese are the acute accent (Áá, Éé, Íí, Óó, Úú), the circumflex (Ââ, Êê, Ôô) and the tilde (Ãã, Õõ). Respectively (in order), the accents mark open, closed and nasal vowels. There are rules that tell when to put an accent in a word. Most of the time, accented syllables are the stressed ones, and some words even have more than one accent, like "órgão", meaning "organ".
Lastly, the language has a "ç" character (C with a cedilla, used for historical reasons. It has a /s/ sound like in the word "soap" and it never appears at the very start or at the very end of a word.