Learn Hardcore Vietnamese: Khách sạn đó sạch nhưng bữa sáng bắt đầu rất trễ. - That hotel is clean, but breakfast starts very late.

[Subject] + là + [noun / noun phrase]
- Đó là khách sạn. = That is a hotel.
- Anh ấy là giáo viên. = He is a teacher.
Sometimes before longer descriptive phrases, especially in more formal style, but it’s not needed in this short, simple sentence.

So:

Khách sạn đó sạch ✅ (natural)
Khách sạn đó là sạch ❌ (sounds unnatural or overly emphatic in a strange way in everyday speech)

What exactly does đó mean here? How is it different from này?

Đó and này are both demonstratives, similar to that and this in English.

này = this (near the speaker)
- khách sạn này = this hotel (the one near me/us, or the one we’re currently in)
đó = that (not near the speaker; can be near the listener or just “that one we both know about”)
- khách sạn đó = that hotel

In the sentence:

Khách sạn đó sạch nhưng bữa sáng bắt đầu rất trễ.
→ You’re talking about a specific hotel, known to both speaker and listener, but conceptually not “right here”.

You could also say:

Khách sạn này sạch nhưng bữa sáng bắt đầu rất trễ.
→ This hotel (we’re staying in it right now) is clean but breakfast starts very late.

So đó vs này is basically that vs this, plus the shared-context feeling: đó often refers to something both people know about but is not “right here” with the speaker.

Why is the order Khách sạn đó sạch and not sạch khách sạn đó or khách sạn sạch đó?

Vietnamese word order here is:

[Noun] + [Demonstrative] + [Predicate adjective]

So:

Khách sạn đó sạch.
Literally: Hotel that clean. → “That hotel is clean.”

Common patterns to compare:

Noun as subject, adjective as predicate (like our sentence)
- Nhà này đẹp. = This house is beautiful.
- Thành phố đó lớn. = That city is big.
Adjective modifying a noun (attributive) Then the adjective usually comes after the noun, but often with a classifier or a number:
- một khách sạn sạch = a clean hotel
- những khách sạn sạch = (those) clean hotels
- căn phòng sạch = a clean room

You generally don’t say:

sạch khách sạn đó ❌ (word order is wrong; sounds like “clean that hotel” as a command.)
khách sạn sạch đó ❌ (strange; could be understood but feels ungrammatical/unnatural for “that clean hotel”.)

So the pattern to remember:

[This/That + noun] + [adjective] = “This/That noun is adjective.”
Khách sạn đó sạch.
Người kia tốt. (That person is nice.)

What is the difference between trễ and muộn? Could we say rất muộn instead of rất trễ?

Trễ and muộn both mean late, and in many contexts they are interchangeable.

trễ
- Common in Southern Vietnamese.
- Very natural in informal and neutral speech.
- Example: Anh đến trễ. = You came late.
muộn
- More common in Northern Vietnamese.
- Also used in formal speech and writing.
- Example: Anh đến muộn. = You came late.

In your sentence:

… bữa sáng bắt đầu rất trễ.
= breakfast starts very late.

You could absolutely say:

… bữa sáng bắt đầu rất muộn. ✅

That would sound a bit more “northern” or neutral/standard. Using trễ is slightly more “southern flavor” but still widely understood.

What does rất do here, and where can it appear? Could I say trễ lắm or rất là trễ instead of rất trễ?

Rất means very and it comes before the adjective:

rất sạch = very clean
rất trễ = very late
rất tốt = very good

So:

bữa sáng bắt đầu rất trễ
= breakfast starts very late.

Alternative intensifiers:

lắm (usually after the adjective)
- trễ lắm = very late
- You can say: Bữa sáng bắt đầu trễ lắm. ✅
  This feels a bit more colloquial/emotional.
rất là + adjective (informal, conversational)
- rất là trễ = very (really) late
- Bữa sáng bắt đầu rất là trễ. ✅
  This can sound more expressive, but in writing or neutral description, plain rất trễ is simpler and cleaner.

So yes, you can replace rất trễ with trễ lắm or rất là trễ, but rất trễ is the most neutral, textbook-style phrasing.

What exactly does bữa sáng mean? How is it different from buổi sáng and ăn sáng?

These three are related but not the same:

bữa sáng
- Literally: morning meal / breakfast
- Refers to the meal itself.
- In the sentence:
  bữa sáng bắt đầu rất trễ = breakfast starts very late (the breakfast service).
buổi sáng
- Means morning (time of day).
- Not specifically a meal.
- Example:
  - Buổi sáng tôi đi làm. = In the morning I go to work.
ăn sáng
- Means to eat breakfast / having breakfast.
- Verb phrase.
- Example:
  - Tôi ăn sáng lúc 7 giờ. = I eat breakfast at 7.

So:

Bữa sáng bắt đầu rất trễ.
= The breakfast service (meal) starts very late.
Buổi sáng bắt đầu rất trễ.
= The morning starts very late (sounds odd; not natural for hotels).
Tôi ăn sáng rất trễ.
= I eat breakfast very late.

In bữa sáng bắt đầu rất trễ, is bữa sáng really the subject? Can “breakfast” start by itself?

Grammatically, yes: bữa sáng is the subject, and bắt đầu is the verb:

bữa sáng = breakfast (the breakfast service period)
bắt đầu = to start / to begin
rất trễ = very late

So:

bữa sáng bắt đầu rất trễ
= Breakfast (service) starts very late.

This is similar to English usage like:

“Breakfast starts at 9.”
where “breakfast” refers to the meal service time organized by the hotel, not breakfast as a physical object.

If you want to make the “agent” explicit, you could say:

Họ bắt đầu phục vụ bữa sáng rất trễ.
= They start serving breakfast very late.
But in the original sentence, it’s perfectly natural to let bữa sáng be the subject.

How do we know this is talking about the present (habitual) and not the past or future? There’s no tense marking.

Vietnamese verbs don’t change form for tense like English. Tense and aspect are mostly shown by:

Time words (yesterday, tomorrow, now, every day…)
Particles like đã (past), đang (progressive), sẽ (future), etc.
Context.

In:

Khách sạn đó sạch nhưng bữa sáng bắt đầu rất trễ.

There’s no đã, đang, or sẽ, and no explicit time word, so it’s understood as a general, timeless description:

That hotel is (generally) clean, but breakfast (there) starts very late.
→ This matches how we describe opinions about a hotel in a review.

To shift the time frame:

Past experience:
Khách sạn đó sạch nhưng bữa sáng đã bắt đầu rất trễ.
= That hotel was clean but breakfast (there) started very late.
Future expectation:
Khách sạn đó sạch nhưng bữa sáng sẽ bắt đầu rất trễ.
= That hotel is clean but breakfast will start very late.

But without these markers, the default reading is general/habitual (like present simple in English).

Should there be a comma before nhưng in writing? And is nhưng mà different from nhưng?

In full written Vietnamese, many people would indeed put a comma:

Khách sạn đó sạch, nhưng bữa sáng bắt đầu rất trễ.

In everyday text messages or informal writing, dropping the comma is also common. Both are understandable.

About nhưng vs nhưng mà:

nhưng = but, however
nhưng mà = also “but”, but often more informal / conversational, sometimes a bit more emotional or emphatic.

You can say:

Khách sạn đó sạch nhưng bữa sáng bắt đầu rất trễ. ✅
Khách sạn đó sạch, nhưng mà bữa sáng bắt đầu rất trễ. ✅ (more casual, spoken-like)

Meaning is basically the same; nhưng mà can sound a bit more like “but actually / but you know…” in tone.

Why don’t we use a classifier like cái or một before khách sạn đó?

Classifiers are very important in Vietnamese, but they aren’t used in every noun phrase.

Some key points:

When you refer to a specific, known thing as the subject, you can often use:
- [Noun] + [đó/này/kia] without a classifier.
- Khách sạn đó sạch. = That hotel is clean. ✅
If you want to say “a hotel” (indefinite, not specific), you normally add a number or quantifier and a classifier:
- một khách sạn sạch = a clean hotel
- vài khách sạn sạch = a few clean hotels
cái is a very general classifier, but using it with khách sạn is usually unnecessary or sounds off:
- cái khách sạn đó ❌ (usually unnatural here; feels childish or wrong)
- Just khách sạn đó is correct.

So the pattern:

khách sạn đó = that (specific) hotel (as a subject)
một khách sạn sạch = a clean hotel (indefinite)

That’s why there’s no cái or một in the original sentence.