Nous sommes quatorze dans la salle.

In French, when you say how many people are in a group that includes us, you often use être:

• Nous sommes quatorze = There are fourteen of us / We are fourteen

French treats this as describing the group’s number, so to be is natural.

Compare:

• Nous sommes quatorze. = There are fourteen of us.
• Il y a quatorze personnes dans la salle. = There are fourteen people in the room.

Both are correct, but they are built differently:

• nous sommes... focuses on our group
• il y a... states that something exists / is present

It means:

• We are fourteen
• more naturally in English: There are fourteen of us

So the speaker is part of a group, and the total number of people in that group is 14.

French often leaves personnes unstated when the meaning is obvious.

So:

• Nous sommes quatorze literally looks like We are fourteen
• but the understood meaning is We are fourteen people / There are fourteen of us

Adding personnes is possible in some contexts, but it is usually unnecessary here.

Because quatorze is a number, not an adjective that agrees like grand / grande / grands / grandes.

Numbers normally do not change form for gender or number:

• Nous sommes quatorze.
• Elles sont quatorze.
• Ils sont quatorze.

In all cases, quatorze stays the same.

Dans la salle means in the room or in the hall, depending on context.

• dans = in
• la salle = the room / the hall

A useful point: salle is often broader than English room. It can mean a room, hall, classroom, or other indoor space depending on the situation.

So:

• Nous sommes quatorze dans la salle. = There are fourteen of us in the room/hall.

La means the, so the speaker is referring to a specific room already known from context.

• dans la salle = in the room
• dans une salle = in a room

If the room is already identified or obvious, French naturally uses la salle.

Yes. That is a very natural alternative.

The difference is mostly one of focus:

• Nous sommes quatorze dans la salle.
  = There are fourteen of us in the room.
  The speaker is part of the group.

• Il y a quatorze personnes dans la salle.
  = There are fourteen people in the room.
  This is a more neutral statement about the number of people present.

So if the speaker wants to emphasize our group, nous sommes quatorze works well.

Yes. That is very common.

French often says:

• Nous sommes trois. = There are three of us.
• Nous sommes dix. = There are ten of us.

English usually prefers there are ... of us, while French often uses we are + number.

So this is one of those cases where a very literal translation sounds less natural in English.

Yes, usually.

• Nous sommes quatorze is standard and works in all contexts.
• On est quatorze is very common in everyday spoken French.

In modern spoken French, on often replaces nous:

• On est quatorze dans la salle.

This means the same thing, but it sounds more conversational.

Yes, there is normally a liaison between sommes and quatorze.

A careful pronunciation would be roughly:

• Nous sommes quatorze → noo som ka-torz
• with liaison: the final s in sommes links to the next word and sounds like z

So you may hear something like:

• noo som-z-ka-torz

Also:

• the s in nous is normally not pronounced here
• quatorze ends with a pronounced z sound

Yes, it is grammatically possible, but it is usually less natural unless you want to be especially explicit.

French normally prefers the shorter version:

• Nous sommes quatorze dans la salle.

Adding personnes can sound a bit heavier because the idea of people is already understood.

Yes. Nous means we, so it includes the speaker.

That is why this sentence means the speaker is one of the fourteen people in the room.

If the speaker were not included, French would use a different structure, for example:

• Ils sont quatorze dans la salle. = There are fourteen of them in the room.
• Il y a quatorze personnes dans la salle. = There are fourteen people in the room.

Because quatorze is part of the main statement about nous:

• Nous sommes quatorze = the core idea
• dans la salle = extra information about location

So the structure is:

• subject
  • verb
    • number
      • place

This is the most natural order in French for this sentence.