Vietnamese ngủ names sleeping, but natural descriptions of sleep depend on what surrounds it. Đi ngủ means go to bed, ngủ thiếp đi means drift/fall asleep, đang ngủ means be asleep, ngủ ngon/ngủ say describes sleep quality or depth, ngủ đủ describes sufficiency, and ngủ quên presents unintended sleep or oversleeping. English often uses one verb plus a tense or adjective where Vietnamese selects a serial frame or result expression.
Ngủ never conjugates. Aspect markers and complements build the event: đã ngủ, đang ngủ, sắp ngủ, ngủ rồi, ngủ được. The grammar maps onset, ongoing state, duration, result, and awakening rather than inflected forms of sleep. This page keeps sống “live/be alive” separate; that predicate has its own reference page.
Construction map
| Frame | Core meaning | Example | Important contrast |
|---|---|---|---|
| ngủ | sleep/be sleeping | em bé ngủ rồi | state/activity from context |
| đi ngủ | go to bed for sleep | đi ngủ lúc mười giờ | not necessarily fall asleep then |
| ngủ thiếp đi | drift/fall asleep | ngủ thiếp đi trên ghế | onset, often unplanned |
| ngủ được | manage/can sleep; achieved duration | ngủ được sáu tiếng | achievement or ability |
| ngủ ngon/say/yên | sleep well/deeply/peacefully | ngủ rất ngon | quality or depth |
| ngủ đủ/đủ giấc | get enough sleep | ngủ đủ tám tiếng | sufficiency |
| ngủ quên | fall asleep unintentionally/oversleep | ngủ quên trên xe | unintended consequence |
| ngủ dậy | wake/get up after sleeping | ngủ dậy lúc sáu giờ | exit from sleep |
Bare ngủ, location, and duration
Ngủ is normally intransitive: the sleeper is its subject, not an object. Location follows a locative phrase (ngủ ở khách sạn, ngủ trên ghế), while duration can follow directly (ngủ tám tiếng, ngủ một lát). A duration after ngủ measures the event; it is not a direct object like food after ăn.
Tối qua tôi ngủ tám tiếng mà sáng nay vẫn thấy mệt.
I slept for eight hours last night, but I still feel tired this morning.
Đứa bé đang ngủ trên xe, anh đóng cửa nhẹ thôi nhé.
The baby is sleeping in the car, so close the door gently. (informal request)
Ngủ với + person literally means sleep with someone and may imply sharing a bed or having sex, depending on participants and context. To say merely that people stayed in the same room, use ngủ cùng phòng với...; to say a child slept beside a caregiver, specify ngủ cạnh... or ngủ chung với... as appropriate. This is a real ambiguity, so precision avoids unintended implications.
Trong chuyến đi, tôi ngủ cùng phòng với hai đồng nghiệp.
On the trip, I shared a room with two colleagues.
Going to bed is not falling asleep
Đi ngủ presents the purposeful transition into the sleep routine: stop other activities and go to bed. It need not mean that sleep begins immediately. Bắt đầu ngủ literally means begin sleeping but is less idiomatic for many everyday reports of falling asleep. Use ngủ thiếp đi for drifting off, especially unintentionally or from exhaustion; chợp mắt means get a little sleep/take a nap.
Tôi đi ngủ lúc mười một giờ nhưng gần một giờ mới ngủ được.
I went to bed at eleven, but I didn’t manage to fall asleep until nearly one.
Anh ấy định đọc thêm vài trang nhưng ngủ thiếp đi trên ghế sofa.
He meant to read a few more pages but drifted off on the sofa.
Tranh thủ lúc chờ chuyến bay, tôi chợp mắt được hai mươi phút.
While waiting for the flight, I managed to get twenty minutes of sleep.
Buồn ngủ means sleepy, literally having the feeling/urge to sleep. It is not the progressive “sleeping.” Mất ngủ means insomnia or inability to sleep, either as a recurring condition or a particular sleepless episode.
Tôi buồn ngủ lắm nhưng cứ nằm xuống là lại không ngủ được.
I’m very sleepy, but whenever I lie down, I still can’t sleep.
Quality, depth, sufficiency, and achieved sleep
Ngủ ngon evaluates sleep as good/restful and also appears in the bedtime wish Ngủ ngon nhé! “Sleep well!” Ngủ say means sleep deeply/soundly, often so the sleeper is hard to wake. Ngủ yên means sleep peacefully or undisturbed and can sound tender or literary in some contexts. Ngủ một mạch means sleep continuously for a stretch (informal/neutral).
Đêm qua trời mát nên cả nhà ngủ rất ngon.
The weather was cool last night, so the whole family slept very well.
Cậu ấy ngủ say đến mức chuông báo thức reo ba lần cũng không nghe thấy.
He was sleeping so soundly that he didn’t hear the alarm ring three times.
Ngủ đủ or ngủ đủ giấc says the amount met a relevant need. Ngủ được instead marks ability, success, or achieved duration. Tôi ngủ được tám tiếng can report that eight hours were achieved; tôi ngủ đủ tám tiếng emphasizes that the full target of eight hours was met.
Tuần này tôi bận nhưng vẫn cố ngủ đủ giấc.
I’m busy this week, but I’m still trying to get enough sleep.
Negation position changes the focus. Không ngủ được is the unmarked “cannot manage to sleep.” Ngủ không được is also frequent in conversation, especially as a focused comment on the attempted activity: “as for sleeping, I can’t.” Both are natural; chưa ngủ được means the desired onset has not yet been achieved.
Phòng bên cạnh ồn quá nên tôi không ngủ được.
The room next door was so noisy that I couldn’t sleep.
Ngủ quên, ngủ nướng, and waking
Ngủ quên marks unintended sleep or an unintended failure caused by sleeping. On transport, ngủ quên can mean doze off and miss awareness; with a scheduled time, it often means oversleep. Add the consequence when the intended meaning could be unclear: ngủ quên nên lỡ bến, ngủ quên mất giờ họp.
Tôi ngủ quên trên xe buýt, đến khi tỉnh dậy thì xe đã đi quá hai bến.
I fell asleep on the bus, and by the time I woke up, it had gone two stops too far.
Ngủ nướng means stay in bed sleeping late for pleasure (informal). It differs from accidental ngủ quên. Dậy muộn/ngủ dậy muộn reports waking or getting up late without necessarily saying why. English sleep late is ambiguous between going to bed late and waking late; Vietnamese should name the intended endpoint.
Chủ nhật tôi thường ngủ nướng, nhưng hôm nay lại phải dậy sớm.
I usually sleep in on Sundays, but today I had to get up early. (informal)
Ngủ dậy and thức dậy both locate waking. Ngủ dậy transparently links the state and its endpoint; thức dậy is the general lexical expression “wake up.” Dậy alone can mean get up and is common when waking is already understood.
Aspect and interaction
Đang ngủ describes the ongoing state. Đã ngủ generally reports that someone slept, while ngủ rồi can mean “has gone to sleep/is asleep now” when current relevance favors that inference. Chưa ngủ means not yet asleep or has not slept, depending on the time frame. Sắp ngủ means about to sleep, often about to go to sleep in conversation.
Em bé ngủ rồi, mọi người nói nhỏ thôi.
The baby is asleep now, so let’s all speak quietly.
Tôi chưa ngủ; anh cứ gọi nếu cần trao đổi gấp.
I’m not asleep yet; call me if you need to discuss something urgent.
Questions distinguish state, quality, and duration: Ngủ chưa? “Are you asleep/have you gone to sleep yet?”, Ngủ ngon không? “Did you sleep well?”, Ngủ được bao lâu? “How long did you manage to sleep?”, Ngủ ở đâu? “Where did you sleep?”
A minimal five-way contrast
| Function | Vietnamese | Interpretation |
|---|---|---|
| affirmative | Đứa bé ngủ rất ngon. | The baby sleeps/is sleeping very well. |
| negative | Tối qua tôi không ngủ được. | I couldn’t sleep last night. |
| question | Đêm qua bạn ngủ được bao lâu? | How long did you manage to sleep last night? |
| aspect-marked | Ông đang ngủ. | Grandpa is sleeping. |
| idiomatic collocation | Tôi ngủ một mạch đến sáng. | I slept straight through until morning. |
The complement tells the sleep story
— Đêm qua cậu ngủ ngon không? — Không. Mười một giờ tôi đi ngủ nhưng mãi không ngủ được. Gần sáng mới ngủ thiếp đi, rồi lại ngủ quên, không nghe thấy chuông báo thức. — Thế hôm nay về sớm mà ngủ bù đi. — Ừ, tối nay tôi phải ngủ đủ giấc.
— Did you sleep well last night? — No. I went to bed at eleven but couldn’t fall asleep for ages. I only drifted off near dawn, then overslept and didn’t hear the alarm. — Then go home early today and catch up on some sleep. — Yes, I need to get enough sleep tonight.
The dialogue separates bedtime (đi ngủ), failed onset (không ngủ được), eventual onset (ngủ thiếp đi), unintended oversleeping (ngủ quên), compensation (ngủ bù), and sufficient rest (ngủ đủ giấc). English repeatedly uses sleep, but Vietnamese complements trace each phase.
Common Mistakes
1. Treating đi ngủ as proof that sleep began. It normally means go to bed.
❌ Tôi đi ngủ lúc mười giờ nên lúc mười giờ tôi đã ngủ.
Faulty inference—going to bed at ten does not guarantee being asleep at ten.
✅ Tôi đi ngủ lúc mười giờ nhưng mười một giờ mới ngủ được.
I went to bed at ten but didn’t manage to fall asleep until eleven.
2. Copying English “be asleep” with là. Vietnamese uses the predicate ngủ, usually with aspect or context.
❌ Em bé là ngủ rồi.
Incorrect—là does not link the subject to this verbal state.
✅ Em bé ngủ rồi.
The baby is asleep now.
3. Giving ngủ a direct object like English “sleep a peaceful sleep.” Express quality with a complement.
❌ Tối qua tôi ngủ một giấc ngủ ngon.
Awkward literal transfer—the noun giấc ngủ redundantly repeats the predicate.
✅ Tối qua tôi ngủ rất ngon.
I slept very well last night.
4. Using ngủ quên for deliberate sleeping in. Ngủ quên implies lack of intention or a missed obligation.
❌ Chủ nhật nào tôi cũng cố tình ngủ quên đến mười giờ.
Contradictory—cố tình makes the sleeping deliberate, while ngủ quên presents it as unintended.
✅ Chủ nhật nào tôi cũng ngủ nướng đến mười giờ.
Every Sunday I sleep in until ten. (informal)
5. Leaving English “sleep late” ambiguous. Name bedtime or waking explicitly.
❌ Hôm qua tôi ngủ muộn.
Potentially ambiguous without context—it may be understood as going to sleep late rather than waking late.
✅ Hôm qua tôi đi ngủ muộn, còn sáng nay tôi ngủ dậy muộn.
Yesterday I went to bed late, and this morning I woke up late.
Key Takeaways
- Ngủ is intransitive; durations measure the sleep event, while locations take ordinary locative phrases.
- Separate đi ngủ (go to bed), ngủ thiếp đi/ngủ được (fall or manage to fall asleep), and ngủ dậy/thức dậy (wake).
- Quality and result expressions are precise: ngủ ngon, ngủ say, ngủ đủ, ngủ quên, ngủ nướng, and ngủ bù are not interchangeable.
- Đang ngủ presents an ongoing state; ngủ rồi often yields the current reading “is asleep now” through discourse relevance.
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