Learn French: Je vais fêter mon anniversaire demain. - I am going to celebrate my birthday tomorrow.

To talk about something that will happen soon, you use the present tense of the verb aller (to go) followed by the infinitive (the unconjugated dictionary form) of your main verb. Here, Je vais means "I am going" and fêter is the infinitive meaning "to celebrate".

Why do we use the infinitive fêter instead of conjugating it?

In French, when two verbs are paired together to express a single idea, the second verb is almost always left in its infinitive form. The first verb, vais, is already conjugated and tells us who is doing the action, so fêter stays untouched.

Does anniversaire mean "birthday" or "anniversary"?

It actually means both! In French, un anniversaire is used for a person's yearly birthday as well as things like a wedding anniversary. If you ever need to be specific about a wedding, you can say un anniversaire de mariage.

Why is it mon anniversaire?

Anniversaire is a masculine noun, so it takes the masculine word for "my", which is mon. As a handy pronunciation tip: even if it were a feminine noun, you would still use mon instead of ma because the word starts with a vowel. This makes the words link together smoothly when speaking.