Bon appétit !

A good approximation is boh-nah-pay-TEE.

More precisely in French IPA, it is /bɔ.na.pe.ti/.

A few pronunciation points:

• bon does not sound like English bon in bonnet
• the on in bon is nasal when the word stands alone, but in this phrase it links into the next word
• appétit has the stress pattern of French, which is much flatter than English, with a slight emphasis at the end
• the final t in appétit is silent

So if you want a natural learner-friendly version, boh-nah-pay-tee is a solid start.

That is because of liaison.

In French, some normally silent final consonants are pronounced when the next word begins with a vowel sound. Since appétit begins with a-, bon links to it:

• bon
  • appétit
• pronounced together as bo-na-pé-ti

This linking is very normal and expected in this expression.

Because appétit is a masculine singular noun.

The adjective bon has to agree with the noun it describes:

• masculine singular: bon
• feminine singular: bonne

Since it is un appétit, the correct form is bon appétit.

That is a great question. While many French adjectives do come after the noun, some very common adjectives often come before it. Bon is one of those.

So:

• un bon repas
• un bon livre
• bon appétit

This is just the normal position for bon in many everyday expressions.

The accent on é is an accent aigu, and it tells you to pronounce é as a clear ay-like sound, not a reduced English uh sound.

So:

• é = a clean ay sound
• appétit = a-pay-tee roughly, though the real French sound is tighter and shorter than English ay

The accent is part of the correct spelling, so in standard French writing you should keep it: appétit.

In correct French, you should write Bon appétit ! with the accent.

Without the accent, French readers will still understand you, but it looks like a spelling mistake. In casual situations online, people sometimes omit accents, but learners should get used to writing them properly.

People say it right before eating or as a meal is being served.

Typical situations:

• at the table just before everyone starts eating
• when serving someone food
• in a restaurant, sometimes a server may say it as your dish arrives
• at home, with family or friends

You generally would not say it long before the meal begins. It belongs to the moment when people are about to eat.

It is neutral and polite. You can use it in both informal and fairly formal situations.

For example, it works with:

• family
• friends
• coworkers
• guests
• customers in a restaurant

It is a very standard expression, not especially slangy and not especially stiff.

Yes, very often.

It is a normal everyday expression in French-speaking contexts. You will hear it at home, at school, at work, and in restaurants.

You may sometimes hear people say that it is not required in every single situation, and habits can vary by family or region, but overall it is absolutely common and natural.

There is no fixed required reply.

Common possibilities are:

• Merci !
• Bon appétit ! back to the other person
• simply smiling and starting the meal

If everyone at the table is about to eat, people often just say it together or say nothing else afterward.

Yes. The expression stays the same.

You can say Bon appétit ! to:

• one person
• two people
• a whole table

Unlike some other parts of French, this phrase does not change depending on the number of people you are addressing.