Excusez-moi, monsieur, à quelle heure commence le feu d’artifice du 14 juillet?

Excusez-moi uses the vous form, so it is polite and appropriate when speaking to a stranger. Since the sentence also includes monsieur, this is clearly a formal situation.

• Excuse-moi = informal, used with one person you know well
• Excusez-moi = formal, used with a stranger, older person, or more than one person

The -z is the ending for the vous imperative of excuser.

In French, when an imperative verb is followed by an object pronoun like moi, toi, nous, or vous, they are joined with a hyphen.

So:

• Excusez-moi = excuse me
• Regardez-nous = look at us
• Asseyez-vous = sit down

This is standard spelling in the imperative.

Monsieur is a polite form of address meaning sir. It makes the sentence more respectful and natural when speaking to an unknown man.

So the beginning of the sentence is basically:

• Excuse me, sir...

You do not always need monsieur, but it is very common in polite spoken French.

French uses à quelle heure literally meaning at what hour.

This is simply the normal French way to ask for a time:

• À quelle heure commence... ? = What time does ... start?
• À quelle heure part le train ? = What time does the train leave?

English uses what time, but French usually uses at what hour.

This is a standard formal question structure in French. After a question phrase like à quelle heure, French can put the verb before the subject:

• À quelle heure commence le feu d’artifice ?

This is more natural and elegant than simply keeping statement word order.

Compare:

• Le feu d’artifice commence à 22 heures. = The fireworks start at 10 p.m.
• À quelle heure commence le feu d’artifice ? = What time do the fireworks start?

This kind of inversion is common in written and careful spoken French.

Hyphens are used in inversion when the subject is a pronoun, not usually when it is a noun.

Compare:

• Commence-t-il à 22 heures ? = Does it start at 10 p.m.?
• À quelle heure commence le feu d’artifice ? = What time do the fireworks start?

Here, le feu d’artifice is a noun phrase, so there is no hyphen.

French usually uses the singular expression un feu d’artifice, literally a firework display.

So:

• le feu d’artifice = the fireworks / the fireworks display

Even though English often uses the plural fireworks, French normally treats it as a singular event or show.

D’ is the shortened form of de before a vowel sound.

So:

• de + artifice becomes d’artifice

The full expression feu d’artifice literally means something like fire of artifice, but you should learn it as a fixed phrase meaning fireworks or fireworks display.

Du is the contraction of de + le.

• de le 14 juillet becomes du 14 juillet

Here, le 14 juillet refers to the 14th of July, which in France is the national holiday often called Bastille Day in English.

So:

• le feu d’artifice du 14 juillet = the fireworks for/of July 14th

This means the fireworks connected with the national holiday celebration.

French dates are expressed differently from English. French simply says:

• le 14 juillet = the 14th of July / July 14

There is no of in the French structure. It is just the number followed by the month.

Examples:

• le 1er mai = May 1st
• le 25 décembre = December 25th

So du 14 juillet is perfectly normal French date wording.

Yes. A more everyday spoken version would be:

• Le feu d’artifice du 14 juillet commence à quelle heure ?

This keeps the normal statement order and puts the question at the end. In everyday conversation, this is very common.

You could also hear:

• Il commence à quelle heure, le feu d’artifice du 14 juillet ?

The original sentence is more careful and polite, especially with Excusez-moi, monsieur.

Here commence means starts or begins.

French present tense often corresponds to the English simple present:

• Le spectacle commence à 8 heures. = The show starts at 8.

Depending on context, the French present can sometimes match English is starting, but in this sentence the natural translation is starts.

A rough pronunciation guide is:

ex-kew-zay mwa, muh-syuh, ah kel ur koh-mahns luh fuh dar-tee-fees dy kat-orz zhwee-yay

A few helpful notes:

• Excusez ends with a z sound: ex-kew-zay
• moi sounds like mwa
• quelle heure has a smooth link in speech and sounds close to kel ur
• feu is a French vowel sound that does not exist exactly in English
• juillet sounds roughly like zhwee-yay

If you want to sound natural, try saying it in groups:

• Excusez-moi, monsieur,
• à quelle heure commence
• le feu d’artifice du 14 juillet ?

Commencer is the infinitive, meaning to begin or to start.
Commence is a conjugated form of that verb.

In this sentence:

• commence = begins / starts

Because the subject is le feu d’artifice, which is third person singular, the verb must be:

• le feu d’artifice commence

So you cannot say à quelle heure commencer le feu d’artifice ? in normal French. You need the conjugated form commence.

Several elements make it polite:

• Excusez-moi = formal excuse me
• monsieur = sir
• formal question structure: à quelle heure commence... ?

French often uses these politeness markers when asking a stranger for information. A native speaker would likely find this sentence very natural in a public setting, especially at an event or in the street.