Learn French: Les enfants vont dire joyeux Noël. - The children are going to say merry Christmas.

To express that something is going to happen in the near future, French uses the conjugated verb aller (to go) followed by an infinitive (an unconjugated verb, which is the form you find in the dictionary). Here, vont is the conjugated form of aller, and dire (to say) is the infinitive. Together, they mean 'are going to say'.

Why do we use vont here instead of another form of aller?

Vont is the form of aller that goes with ils or elles (they). Because les enfants (the children) is a plural group, it acts just like ils (they). Therefore, we say les enfants vont (the children are going to).

Is the 's' at the end of Les pronounced in this sentence?

Yes, it is! Normally, the 's' at the end of les is silent. However, because the next word enfants starts with a vowel, you must link the two words together when speaking. This connection is called a liaison, and it makes the 's' sound like a 'z'.

Doesn't the adjective usually come after the noun in French? Why is it joyeux Noël?

You are right that most French adjectives come after the noun! However, short, common adjectives that describe goodness, age, beauty, or size (often remembered as BANGS) generally come before the noun. Joyeux (merry or happy) is one of these exceptions and acts as a set greeting here.