English requires a form of be in the room is small, so English-speaking learners often produce Phòng này là nhỏ. Neutral Vietnamese uses a different construction: a property word such as nhỏ, đẹp, nóng, or vui can be the predicate by itself. The ordinary sentence is Phòng này nhỏ.
The useful repair is not “delete every là before something translated as an adjective.” Vietnamese uses là for nominal identity and classification, and it also appears in marked formal or emphatic property frames. A good diagnosis asks which Vietnamese predicate construction the speaker needs. This page keeps subject and object omission outside its scope; that separate decision is covered on Common Mistakes with Subject and Object Omission.
The three-way decision
| Intended job | Vietnamese pattern | Example |
|---|---|---|
| Describe a property | subject + property predicate | Phòng này nhỏ. |
| Identify or classify | subject + là + noun phrase | Phòng này là phòng họp. |
| Highlight an assessment | marked frame such as đúng là, thật là, rất là, or formal là + abstract property | Phòng này đúng là nhỏ thật. |
Use this editing test:
- Are you saying what kind of entity the subject is? Use là + noun phrase.
- Are you simply saying what it is like? Use the property directly.
- Is the speaker explicitly confirming, exclaiming, or presenting an abstract evaluation as a conclusion? Keep the relevant marked frame and label its register.
Error pattern 1: adding là to an ordinary property
❌ Căn hộ này là rộng và sáng.
Incorrect as a neutral description: là has been copied from English ‘is.’
✅ Căn hộ này rộng và sáng.
This apartment is spacious and bright.
Rộng và sáng is already a coordinated stative predicate. Degree expressions attach without a copula too:
❌ Hôm nay trời là rất nóng.
Incorrect as a neutral statement: rất nóng predicates directly.
✅ Hôm nay trời rất nóng.
It is very hot today.
The same logic survives negation and aspect. Say không mới “not new,” đã cũ “has become/was already old,” and đang yên tĩnh “is quiet at the moment,” not không là mới, là đã cũ, or là đang yên tĩnh in ordinary description.
Error pattern 2: deleting là from a nominal identity
Some learners overcorrect and remove là everywhere. An equation that identifies someone by profession, role, name, or category normally has a nominal predicate and needs là in a complete neutral clause.
❌ Anh Quân trưởng nhóm của dự án này.
Incorrect as a complete neutral identification: trưởng nhóm is a noun phrase.
✅ Anh Quân là trưởng nhóm của dự án này.
Mr. Quân is the team leader for this project.
❌ Đây căn hộ mới của gia đình tôi.
Incorrect neutral identification: the demonstrative subject needs là before the noun phrase.
✅ Đây là căn hộ mới của gia đình tôi.
This is my family's new apartment.
Notice that mới follows căn hộ inside the noun phrase. The presence of an adjective somewhere after là does not make the structure là + adjective.
Minimal contrast: description versus identification
Căn nhà này đẹp.
This house is beautiful. (A property is asserted.)
Đây là căn nhà đẹp nhất khu phố.
This is the most beautiful house in the neighborhood. (A house is identified.)
In the second sentence, là links đây to the full noun phrase căn nhà đẹp nhất khu phố. Removing căn nhà would not produce the same neutral structure. English hides this difference because both predicates contain is.
A grammatical form that means something else
Compare a neutral description with a marked confirmation:
Căn này đẹp.
This place is beautiful. (Neutral description.)
Căn này đúng là đẹp thật.
This place really is beautiful. (The speaker confirms an assessment, conversational and emphatic.)
The second sentence is fully grammatical, but đúng là ... thật adds speaker commitment: perhaps the listener recommended the apartment and the speaker now agrees. Replacing it mechanically with the bare predicate would remove that discourse meaning.
Bare là + property also occurs in restricted marked uses, especially with abstract assessments in formal argumentation:
Trong hoàn cảnh này, giữ im lặng là cần thiết.
In these circumstances, remaining silent is necessary. (formal)
Nhận xét ấy là đúng, nhưng chưa đủ để bác bỏ giả thuyết.
That observation is correct, but it is not sufficient to reject the hypothesis. (formal)
These patterns present cần thiết or đúng as the asserted evaluation. They do not license everyday Cái bàn này là nhỏ. The conservative A2 production rule remains: use ordinary properties directly; learn formal là cần thiết / là đúng / là quan trọng as registered constructions.
Error pattern 3: misanalyzing emphatic frames
Thật là, rất là, and đúng là behave as larger expressive frames. Do not extract là and insert it into every description.
Bức ảnh này thật là đẹp!
This photo is truly beautiful! (expressive)
Quán này rất là đông vào tối thứ Bảy.
This place gets really crowded on Saturday nights. (informal, emphatic)
Neutral Bức ảnh này đẹp and Quán này rất đông vào tối thứ Bảy remain possible. The marked versions convey exclamation or conversational intensity. In formal edited prose, plain rất đông is usually safer than colloquial rất là đông unless the writer is reproducing a voice.
Dialogue repair: ask what the predicate is doing
❌ A: Căn hộ mới thế nào? — B: Nó là nhỏ, nhưng vị trí đẹp. Đây gần trường.
A: What is the new apartment like? — B: It is small, but the location is nice. This is near the school. The answer inserts là before a property and omits it from an identification.
✅ A: Căn hộ mới thế nào? — B: Nó nhỏ nhưng sáng. Điều tiện nhất là căn hộ ở rất gần trường.
A: What is the new apartment like? — B: It is small but bright. The most convenient thing is that the apartment is very close to the school.
The repaired first clause uses direct property predicates nhỏ and sáng. In Điều tiện nhất là..., the phrase before là names “the most convenient thing,” and the following clause specifies what that is. The construction is identificational, not evidence that tiện or the location predicate ở gần requires a copula.
Six English-triggered repairs at a glance
| English-driven attempt | Repair | Why |
|---|---|---|
| Nhà này là đẹp. | Nhà này đẹp. | ordinary property predicate |
| Trời là lạnh. | Trời lạnh. | weather property predicates directly |
| Cô ấy là rất vui. | Cô ấy rất vui. | rất modifies the property without là |
| Chiếc xe không là mới. | Chiếc xe không mới. | không directly negates the stative predicate |
| Anh Nam bác sĩ. | Anh Nam là bác sĩ. | profession is a nominal classification |
| Đây căn phòng nhỏ. | Đây là căn phòng nhỏ. | the full noun phrase identifies the referent |
Register and regional notes
Direct property predicates and nominal là are standard nationwide. Conversational emphasis varies by speaker and region, but rất là and đúng là are broadly understood; do not respell them to imitate pronunciation. Formal prose uses evaluative frames such as là cần thiết more readily than casual conversation. Literary prose may omit recoverable material or balance nominal equations for style, but those effects are not a reason to insert là into basic A2 descriptions.
Common Mistakes
1. Treating every post-là property word as an error
❌ Người học sửa ‘Điều đó là đúng’ thành ‘Điều đó đúng’ trong mọi ngữ cảnh.
Bad editing strategy: the learner replaces formal marked ‘That is true’ in every context.
✅ Trong báo cáo trang trọng, ‘Điều đó là đúng’ có thể nhấn mạnh kết luận; trong lời nói trung tính, ‘Điều đó đúng’ gọn hơn.
In a formal report, ‘Điều đó là đúng’ can foreground the conclusion; in neutral speech, ‘Điều đó đúng’ is more concise.
The first form is not ungrammatical; register and information structure decide whether it is apt.
2. Letting English word class decide Vietnamese syntax
❌ Tôi dùng là vì ‘tired’ là tính từ trong tiếng Anh.
Incorrect reasoning: I use là because ‘tired’ is an adjective in English.
✅ Hôm nay tôi mệt nên về sớm.
I'm tired today, so I'm going home early.
Vietnamese mệt is a stative predicate in this clause. Its English dictionary label does not supply Vietnamese syntax.
3. Leaving là before a property with another marker
❌ Căn phòng này là đã cũ rồi.
Incorrect as the neutral meaning ‘This room is old now.’
✅ Căn phòng này đã cũ rồi.
This room is old now.
For self-editing, underline the entire complement after the subject. If its head is a noun phrase, choose nominal là. If it directly describes a property, remove copied English be. If a marked frame remains, name its extra meaning—confirmation, exclamation, focus, or formal evaluation—before keeping it.
Key Takeaways
- Ordinary properties predicate directly: Nhà đẹp, not neutral Nhà là đẹp.
- Identity and classification use là + noun phrase: Lan là bác sĩ.
- A property inside a noun phrase does not change the rule: Đây là căn nhà đẹp identifies a house.
- Keep marked đúng là, thật là, rất là, and formal là + abstract property only when their emphasis or register is intended.
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Start learning Vietnamese →Related Topics
- Property Words as Stative PredicatesA1 — Describe qualities directly with Vietnamese property predicates, without inserting là, and place degree words such as rất, lắm, hơi, and quá correctly.
- When Là Appears before a Property ExpressionA2 — Distinguish neutral copula-free property predicates from marked, formal, and identificational constructions containing là.
- Choosing Là versus Zero CopulaA1 — Choose là for identity and noun classification, and use zero copula for properties, age, and selected contextual patterns.
- Là for Classification and IdentificationA2 — Use là to identify a person or thing, assign it to a noun-defined class, and distinguish this pattern from property, location, possession, and existence clauses.
- Common Mistakes with Pronouns and Address TermsA2 — Diagnose English-driven person-reference errors by choosing a coherent Vietnamese relationship pair rather than translating I and you word for word.
- Common Mistakes with Subject and Object OmissionA2 — Decide when Vietnamese participants are recoverable enough to omit and when ambiguity, contrast, or social meaning requires them to be stated.