Nous faisons la fête ce soir.

Because faisons is the nous form of the verb faire in the present tense.

The verb faire is irregular, so its forms do not all look predictable:

• je fais
• tu fais
• il / elle fait
• nous faisons
• vous faites
• ils / elles font

So Nous faisons simply means we do / we are doing.

French often uses an idiomatic expression where English might prefer a single verb.

Faire la fête is a very common expression meaning:

• to party
• to celebrate
• to have a festive time

Even though faire usually means to do or to make, in this expression you should learn the whole chunk faire la fête as one unit.

Because the normal expression is faire la fête, with the definite article.

In French, many idiomatic expressions include an article where English would not. So this is not something you usually drop. La fête is part of the fixed phrase.

A good way to remember it is:

• faire la fête = the standard expression
• not faire fête

Ce soir is a time expression meaning this evening / tonight.

It tells you when the action happens. In the sentence, it works like an adverbial phrase of time.

French often places this kind of time expression at the end of the sentence:

• Nous faisons la fête ce soir.

But it could also appear earlier for emphasis:

• Ce soir, nous faisons la fête.

Both are natural.

Because soir is a masculine singular noun.

The demonstrative adjectives are:

• ce for masculine singular
• cette for feminine singular
• ces for plural

So:

• ce soir = this evening / tonight

Compare:

• ce matin = this morning
• cette nuit = tonight / this night

Since soir is masculine, ce is the correct form.

Because French, like English, can use the present tense for a planned or expected near-future action.

So Nous faisons la fête ce soir uses the present tense, but the time phrase ce soir makes it clear that the event is later today.

This is very natural. English does something similar:

• We’re partying tonight
• We leave tomorrow

French could also use a future form in some contexts, but the present is very common for scheduled or intended actions.

Sometimes, but in everyday spoken French, on is often more common than nous.

So in conversation, many speakers would naturally say:

• On fait la fête ce soir.

That means the same thing as Nous faisons la fête ce soir in most contexts.

A useful rule:

• nous is completely correct and common in writing, formal speech, or careful speech
• on is extremely common in everyday spoken French

Not exactly.

• faire la fête usually means to party, to celebrate in a lively way, or to have fun
• fêter often means to celebrate a specific event, holiday, or person

For example:

• Nous faisons la fête ce soir = we’re partying tonight
• Nous fêtons son anniversaire ce soir = we’re celebrating his/her birthday tonight

So fêter is often more directly tied to a specific object or occasion.

A simple pronunciation guide is:

noo fuh-zon la fet suh swar

A few details:

• Nous sounds like noo
• faisons has a z sound in the middle: fuh-zon
• fête sounds roughly like fet
• soir sounds like swar

Also, the -nt ending is not an issue here because faisons ends in -ons, pronounced with a nasal sound.

The word order is actually very typical French:

• Nous = subject
• faisons = verb
• la fête = expression/object-like part of the idiom
• ce soir = time expression

So it follows the common pattern:

subject + verb + rest of sentence + time expression

That makes this a very useful model for building other sentences. For example:

• Nous mangeons au restaurant ce soir.
• Nous regardons un film ce soir.

So the structure is straightforward, even if faire la fête itself is idiomatic.