Mỗi phòng thử đồ đều có ghế.

Yes, they are related, but they do different jobs.

• mỗi = each / every
• đều = all / uniformly / without exception

In Vietnamese, mỗi ... đều ... is a very common pattern meaning each/every ... all .... It sounds natural and emphasizes that the statement applies to every member of the group.

So:

• Mỗi phòng thử đồ đều có ghế.
  = Every fitting room has a chair / chairs.

You can think of mỗi as introducing the items one by one, and đều as confirming that the statement is true for all of them.

Yes, it often can.

• Mỗi phòng thử đồ có ghế.

This is still understandable and grammatical. But đều makes the sentence sound more complete and natural in this kind of every X has Y statement.

So:

• Mỗi phòng thử đồ có ghế. = understandable
• Mỗi phòng thử đồ đều có ghế. = more standard/natural, with stronger every single one emphasis

Phòng thử đồ means fitting room, changing room, or dressing room in a store.

It breaks down like this:

• phòng = room
• thử = try
• đồ = clothes / things / items

So literally, it is something like room for trying on clothes.

In real usage, phòng thử đồ is the normal way to say a store fitting room.

Here, có means have / has.

So:

• phòng thử đồ có ghế = the fitting room has a chair / has chairs

Vietnamese often uses có for possession or existence, depending on context.

Some examples:

• Tôi có xe. = I have a car.
• Phòng có cửa sổ. = The room has a window.
• Trong phòng có ghế. = There is a chair / there are chairs in the room.

In your sentence, có is basically has.

Vietnamese usually does not require articles like a, an, or the the way English does.

So ghế can mean:

• a chair
• the chair
• chairs
• seating

The exact meaning depends on context.

In Mỗi phòng thử đồ đều có ghế, English might translate it as:

• Each fitting room has a chair
• Every fitting room has chairs
• Every fitting room has seating

The Vietnamese sentence itself does not force one exact article choice.

Not necessarily.

Because ghế appears without a number word, it is just the noun chair/seat in a general sense. Depending on context, it could mean:

• one chair
• some chairs
• seating available

If you wanted to clearly say one chair, you could say:

• Mỗi phòng thử đồ đều có một cái ghế.

That specifically means Each fitting room has one chair.

So the original sentence is a bit more general.

Vietnamese often does not mark singular vs. plural unless it matters.

In this sentence:

• mỗi phòng thử đồ already tells you we are talking about each fitting room
• ghế is left general, and the listener understands the number from context

English forces you to choose between chair and chairs, but Vietnamese often does not.

That is very normal.

The structure is:

• Mỗi + noun + đều + có + noun

So here:

• Mỗi = each/every
• phòng thử đồ = fitting room
• đều = all, without exception
• có = have/has
• ghế = chair/seat

A very literal breakdown would be:

• Each fitting room all has chair(s).

That sounds unnatural in English, but it shows how the Vietnamese sentence is built.

It can correspond to both.

• mỗi phòng = each room
• mỗi phòng = every room

In many sentences, English each and every are both possible translations. The difference is usually not very important when learning the Vietnamese grammar.

In this sentence, the most natural English translation is probably:

• Every fitting room has a chair.

But Each fitting room has a chair is also fine.

Yes, sometimes.

Ghế often means chair, but depending on context it can also mean seat.

So possible translations include:

• Every fitting room has a chair.
• Every fitting room has seating.
• Each fitting room has a seat.

If the context is a store fitting room, chair is probably the clearest basic translation.

It could be either, depending on context.

By itself, the sentence can mean:

• a general statement: Fitting rooms all have chairs
• a statement about one particular store: Every fitting room here has a chair

Vietnamese often leaves that kind of specificity to context. There is no article like the to force one interpretation.

So the sentence is naturally flexible.