Learn Portuguese (Portugal): Tu não bebes o leite?

Bebes comes from the regular verb beber (to drink). To match the subject tu (you, informal), you drop the -er ending and add -es. This is the standard rule for regular -er verbs in the present tense.

Why does não come right after tu? In English we say 'Don't you...'

In Portuguese, making a sentence negative is very straightforward: you simply place não directly in front of the verb. You do not change the word order or flip words around for a negative question like we do in English.

How do you make this a question without a word like 'do' or 'does'?

Portuguese does not use helper words to ask questions. You just take the normal statement, keep the exact same word order, and say it with a rising tone of voice (or add a question mark in writing).

Do I have to include the pronoun tu?

No, it is optional. Because the verb ending -es in bebes is only ever used with tu, the listener already knows exactly who you are talking about. You could simply ask: Não bebes o leite?

The word leite ends in 'e'. How do I know to use the masculine article o?