Vietnamese predicates do not change form to agree with the subject or to carry tense. Ăn means “eat” with tôi “I,” bạn “you,” and họ “they”; there is no ending corresponding to English eat/eats/ate/eaten. The predicate also has no separate infinitive form.
This does not mean Vietnamese lacks time grammar. It means that temporal and viewpoint information is packaged around an invariant predicate: a time phrase can locate the event, context can supply an understood time, and separate words such as đã, đang, and sẽ can highlight completion/current progression, prior relevance, or prospective reference. None of those words is a suffix, and none is a mandatory one-for-one tense label.
The broader inventory of verbal, property, nominal, locative, and existential predication is introduced on What Counts as a Vietnamese Predicate.
One form for every person and number
The complete “paradigm” of ăn is strikingly short because the predicate never changes:
| Subject | Vietnamese | English |
|---|---|---|
| tôi “I” | Tôi ăn cơm. | I eat rice / I am eating. |
| bạn “you” | Bạn ăn cơm. | You eat rice / You are eating. |
| họ “they” | Họ ăn cơm. | They eat rice / They are eating. |
Tôi ăn sáng ở nhà, còn anh Nam ăn ở công ty.
I eat breakfast at home, while Nam eats at work.
English adds -s in Nam eats but not in I eat. Vietnamese uses ăn in both clauses. The same principle holds for every predicate: tôi đi / họ đi, bạn thấy / cô ấy thấy, chúng tôi làm / anh ấy làm.
A three-point timeline
Time adverbials can establish past, present, or future reference. Separate aspect or temporal words may make the viewpoint more explicit.
| Time | Vietnamese | What marks the reading |
|---|---|---|
| past | Hôm qua tôi ăn cơm ở nhà. | hôm qua “yesterday”; no changed verb |
| current ongoing event | Bây giờ tôi đang ăn cơm. | bây giờ
|
| future/prospective | Ngày mai tôi sẽ ăn cơm với gia đình. | ngày mai
|
Hôm qua tôi ăn cơm ở nhà.
Yesterday I ate at home.
Bây giờ tôi đang ăn cơm, lát nữa gọi lại nhé.
I'm eating now; call back in a little while.
Ngày mai tôi sẽ ăn cơm với gia đình.
Tomorrow I'll eat with my family.
In all three, ăn is identical. The surrounding expressions build the temporal interpretation. English forces a tense choice on every finite verb; Vietnamese speakers can leave time unmarked when it is already clear.
A bare predicate can refer to different times
A Vietnamese clause does not need đã merely because its English translation uses the past tense.
Sáng nay tôi gặp chị Lan ở ga.
I met Lan at the station this morning.
Sáng nay locates the meeting. Adding đã is possible if the speaker wants to present the event as realized or prior relative to the discourse, but it is not a compulsory “past-tense marker.”
Tôi gặp chị Lan rồi; chị ấy vẫn khỏe.
I've seen Lan; she's still doing well.
Here sentence-final rồi presents the event as achieved or a new resulting state. It does not conjugate gặp. The choice between a bare predicate, đã, rồi, or both depends on aspect and discourse, not only calendar time.
Future time can also be clear without sẽ:
Mai tôi đi Đà Nẵng, chủ nhật mới về.
I'm going to Da Nang tomorrow and won't be back until Sunday.
The scheduled plan plus mai makes the future reading obvious. Adding sẽ can emphasize prediction, intention, or prospective orientation, but it is not mandatory in every future sentence.
Đã, đang, and sẽ are separate words
These high-frequency items appear before the predicate and remain independent:
| Word | Core contribution | Example |
|---|---|---|
| đã | prior/realized situation, often with present relevance | Tôi đã gửi email. “I have sent the email.” |
| đang | ongoing situation at a reference point | Tôi đang gửi email. “I am sending the email.” |
| sẽ | prospective, predicted, or intended situation | Tôi sẽ gửi email. “I will send the email.” |
Tôi đã gửi hợp đồng cho chị rồi.
I've already sent you the contract.
Anh ấy đang nói chuyện với khách hàng.
He is talking to a customer.
Chúng tôi sẽ trả lời trước thứ Sáu.
We will reply before Friday.
The predicate form stays gửi, nói, or trả lời. Negation also remains separate: không ăn “not eat,” chưa ăn “not have eaten yet,” sẽ không ăn “will not eat.” There is no fusion comparable to English didn't.
Modal expressions take the same predicate form
After modal words and expressions, Vietnamese does not switch to an infinitive. The same form appears:
Tôi có thể làm việc ở nhà ngày mai.
I can work from home tomorrow.
Bạn nên nghỉ một lát.
You should rest for a while.
Họ muốn đi sớm để tránh tắc đường.
They want to leave early to avoid traffic.
English contrasts she works with she can work, removing the -s after a modal. Vietnamese has no such alternation: cô ấy làm việc and cô ấy có thể làm việc use the same làm việc. The modal precedes the unchanged predicate.
No conjugation does not mean no lexical grammar
The morphology is simple, but predicates differ in aspectual behavior and complement patterns. Đến “arrive” naturally has an endpoint; biết “know” is stative; ăn can take an object; ngủ normally does not. Đang combines readily with a bounded event in progress, while a stative predicate may need a contrastive context for a progressive reading. The absence of endings does not erase these distinctions.
Likewise, subject choice affects address and social meaning even though it does not affect the predicate form. Vietnamese pronouns and kin terms encode age, relationship, and stance. Em ăn chưa?, Anh ăn chưa?, and Bác ăn chưa? all use ăn, but the subject/address term changes the interpersonal relationship.
Bà ăn sáng chưa ạ?
Have you had breakfast, Grandma/ma'am?
The unchanged predicate is morphologically simple; bà, chưa, and ạ carry person, aspect, and politeness information elsewhere in the clause.
A natural time sequence
A: Cậu gửi hồ sơ chưa? B: Tối qua mình gửi rồi. Bây giờ mình đang chờ phản hồi; nếu mọi việc thuận lợi, tuần sau mình sẽ đi phỏng vấn.
A: Have you sent the application yet? B: I sent it last night. Now I'm waiting for a response; if everything goes well, I'll go to an interview next week.
The forms gửi, chờ, and đi never change. Tối qua plus rồi presents a completed event; bây giờ plus đang presents a current ongoing state; tuần sau plus sẽ presents a prospective event.
Common Mistakes
1. Inventing agreement endings for a third-person subject.
❌ Anh ấy ăn-s cơm lúc mười hai giờ.
Incorrect: Vietnamese does not add an English-style third-person ending.
✅ Anh ấy ăn cơm lúc mười hai giờ.
He eats lunch at twelve.
The predicate is ăn with every subject.
2. Treating đã as a compulsory past-tense prefix.
⚠️ Hôm qua tôi đã đi chợ, đã mua rau và đã gặp cô Hoa.
Grammatical, but often heavy in a neutral narrative if đã is repeated mechanically before every past event.
✅ Hôm qua tôi đi chợ, mua rau và gặp cô Hoa.
Yesterday I went to the market, bought vegetables, and met Hoa.
The opening hôm qua establishes past time for the sequence. Use đã when its realized/prior viewpoint adds something, not as obligatory agreement with “past.”
3. Expecting an infinitive after a modal.
❌ Tôi có thể để làm việc ở nhà.
Incorrect calque using an extra linking word as English ‘to.’
✅ Tôi có thể làm việc ở nhà.
I can work from home.
The modal expression có thể is followed directly by the unchanged predicate làm việc.
4. Moving aspect words after the verb as if they were endings.
❌ Tôi ăn đang cơm.
Incorrect placement of đang.
✅ Tôi đang ăn cơm.
I am eating.
Đang is a separate pre-predicate word, not a suffix.
5. Dropping Vietnamese tone marks because the form is ‘unchanged.’
✅ Tôi sẽ ăn cơm với họ.
I will eat with them. Every tone and vowel mark is obligatory in standard spelling.
The predicate does not conjugate, but every syllable must retain its correct vowel and tone spelling. Never submit an ASCII-only version as Vietnamese text.
Key Takeaways
Vietnamese uses one predicate form for every person, number, and time reference. A time adverbial may be enough; đã, đang, and sẽ are optional independent words with aspectual and discourse work, not compulsory tense affixes. Modals take the same unchanged predicate. “No conjugation” therefore describes where grammar is expressed—not an absence of temporal, aspectual, lexical, or interpersonal structure.
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Start learning Vietnamese →Related Topics
- What Counts as a Vietnamese PredicateA1 — Identify verbal, property, nominal, locative, possessive, and existential predicates without forcing every Vietnamese clause into an English be-plus-adjective pattern.
- Transitive and Intransitive PredicatesA1 — Distinguish predicates that take a direct object from those that do not, and recognize object omission, lexical complement frames, and ambitransitive alternations.
- Predicate EllipsisB2 — How Vietnamese leaves a recoverable predicate unspoken in answers, contrasts, and coordinated clauses.
- Sắp Sửa and Formal ImminenceB1 — Use sắp sửa for deliberate, often written presentation of an approaching event while recognizing its overlap with ordinary sắp.