Learn Romanian: Noi nu cântăm acum. - We are not singing now.

It comes from the regular Conjugation 1 verb a cânta (to sing). To make the "we" form, you drop the final -a from the dictionary form and add the ending -ăm.

Why isn't there a word for "are" to translate "are not singing"?

Romanian does not have a separate continuous tense like the English "are singing". The present tense verb cântăm translates to both "we sing" and "we are singing". The adverb acum (now) makes it clear that the action is happening right at this moment.

Is the pronoun noi required in this sentence?

No, it is optional. Since the ending -ăm on cântăm already tells us the subject is "we", you can simply say Nu cântăm acum. Using noi just adds a bit of emphasis.

What is the rule for placing the negative word nu?

The negative word nu always goes directly in front of the verb. It stays glued to the front of the verb even if you choose to drop the subject pronoun.