Postverbal ไหว asks whether a person or system has enough capacity to cope with a particular demand. The limiting resource may be strength, stamina, attention, time, emotional tolerance, or workload. เดินต่อไหว means “can manage walking farther”; ทำคนเดียวไม่ไหว means “cannot handle doing it alone.”
English usually translates ไหว with can, but Thai distinguishes this demand-based capacity from learned เป็น and broad practical ได้. Someone may know how, have permission, and still not have enough energy to manage.
Put ไหว after the demand
The productive frame is subject/topic + [complete event or burden] + ไหว. In the negative, place ไม่ immediately before ไหว.
| Productive frame | Substitution | Natural result | Capacity being tested |
|---|---|---|---|
| [event phrase] + ไหว | ยกกล่องนี้คนเดียว | ยกกล่องนี้คนเดียวไหว | strength |
| เดินต่ออีกสองกิโลเมตร | เดินต่ออีกสองกิโลเมตรไหว | stamina | |
| รออีกครึ่งชั่วโมง | รออีกครึ่งชั่วโมงไหว | patience or schedule | |
| รับงานเพิ่ม | รับงานเพิ่มไหว | workload | |
| ฟังเรื่องนี้ต่อ | ฟังเรื่องนี้ต่อไหว | attention or emotional tolerance |
กล่องนี้หนักมาก คุณยกคนเดียวไหวไหมคะ
klong ni nak mak khun yok khon diao wai mai kha
This box is very heavy. Can you manage lifting it alone? (ordinary polite question, female speaker; strength against a load)
ผมเดินต่ออีกสองกิโลเมตรไหวครับ
phom doen to ik song kilomet wai khrap
I can manage walking another two kilometers. (ordinary polite speech, male speaker; remaining stamina)
วันนี้งานเยอะมาก ฉันทำคนเดียวไม่ไหวค่ะ
wan ni ngan yoe mak chan tham khon diao mai wai kha
There is a lot of work today; I can't manage it alone. (ordinary polite workplace speech, female speaker; workload exceeds capacity)
The complete burden comes before ไหว. English places can before its verb, but Thai first names the task and then evaluates whether it is manageable.
Capacity is relative, not a permanent trait
ไหว normally assumes a concrete or recoverable demand. The same person may cope today and fail tomorrow because the load, health, time, or emotional situation has changed.
เมื่อคืนฉันนอนน้อย วันนี้ฉันนั่งประชุมสามชั่วโมงไม่ไหวค่ะ
muea khuen chan non noi wan ni chan nang prachum sam chua mong mai wai kha
I slept very little last night; I can't manage sitting through a three-hour meeting today. (ordinary polite workplace speech, female speaker; temporary mental and physical capacity)
ถ้าพักสิบนาที ผมน่าจะทำต่อไหวครับ
tha phak sip nathi phom na cha tham to wai khrap
If I rest for ten minutes, I should be able to keep going. (ordinary polite speech, male speaker; predicted recovery of capacity)
เรื่องนี้กดดันมาก เขารับมือคนเดียวไม่ไหวค่ะ
rueang ni kotdan mak khao rap mue khon diao mai wai kha
This matter is very stressful; she can't handle it alone. (ordinary polite report, female speaker; emotional burden)
Positive ไหว often sounds like a response to a concern, even when the concern is not spoken aloud. กินไหวครับ at a large meal means “I can manage eating it”; it does not state a general eating skill.
ไหว versus ได้ and เป็น
The three common postverbal “can” constructions choose different sources:
คุณนิดขับรถเป็นค่ะ
khun nit khap rot pen kha
Khun Nit knows how to drive. (ordinary polite report, female speaker; learned skill)
วันนี้คุณนิดขับรถได้ครับ รถซ่อมเสร็จแล้ว
wan ni khun nit khap rot dai khrap rot som set laeo
Khun Nit can drive today; the car has been repaired. (ordinary polite report, male speaker; practical opportunity restored)
เมื่อคืนคุณนิดแทบไม่ได้นอน วันนี้ขับรถไหวไหมคะ
muea khuen khun nit thaep mai dai non wan ni khap rot wai mai kha
Khun Nit barely slept last night. Can she manage driving today? (ordinary polite question, female speaker; present stamina)
เป็น commits only to know-how. ได้ presents the event as possible or available. ไหว compares resources with the current demand. These meanings overlap in real situations but are not synonyms.
The Thai ability overview places all three postverbal choices beside formal สามารถ.
Negation and the threshold marked by แล้ว
Event + ไม่ไหว says the demand exceeds capacity. Adding final แล้ว often means that an earlier ability to cope has now reached its limit: ทำต่อไม่ไหวแล้ว “can't keep doing it anymore.”
ฉันกินต่อไม่ไหวแล้วค่ะ อิ่มมาก
chan kin to mai wai laeo kha im mak
I can't eat any more; I'm very full. (ordinary polite speech, female speaker; capacity threshold now crossed)
เขารับแรงกดดันไม่ไหวแล้วครับ เลยขอลาพัก
khao rap raeng kotdan mai wai laeo khrap loei kho la phak
He couldn't take the pressure anymore, so he asked for leave. (ordinary polite report, male speaker; changed capacity state)
Without แล้ว, ไม่ไหว simply evaluates the relevant demand. With แล้ว, the speaker often contrasts the new limit with an earlier period of coping or with an expectation that coping would continue.
Do not replace this with preverbal ไม่ได้. ไม่ได้ยกกล่อง says no lifting occurred; ยกกล่องไม่ไหว says lifting exceeds capacity.
เมื่อเช้าผมไม่ได้ยกกล่องครับ เพื่อนยกให้
muea chao phom mai dai yok klong khrap phuean yok hai
I didn't lift the box this morning; a friend did it for me. (ordinary polite narrative, male speaker; event did not occur)
กล่องหนักเกินไป ผมยกไม่ไหวครับ
klong nak koen pai phom yok mai wai khrap
The box is too heavy; I can't lift it. (ordinary polite speech, male speaker; insufficient strength)
Projected and continuing capacity
จะ + event + ไหวไหม projects a demanding event and asks whether the participant will cope. ยังไหวอยู่ says that capacity is still holding at the reference point.
พรุ่งนี้ต้องเดินทั้งวัน คุณจะเดินไหวไหมคะ
phrung ni tong doen thang wan khun cha doen wai mai kha
Tomorrow we have to walk all day. Will you manage? (ordinary polite question, female speaker; projected stamina)
ตอนนี้ยังไหวอยู่ครับ แต่ขอพักหลังถึงยอดเขา
ton ni yang wai yu khrap tae kho phak lang thueng yot khao
I'm still managing for now, but I'd like to rest after we reach the summit. (ordinary polite reply, male speaker; capacity currently maintained)
Here อยู่ maintains the state ไหว; it does not make the walking event progressive. To report the actual activity, say กำลังเดินอยู่. To report its manageability, say เดินไหว. Combining every marker because English uses be able to keep walking produces unnatural stacks.
พวกเขากำลังเดินขึ้นเขาอยู่ค่ะ แต่ไม่แน่ใจว่าจะเดินไปถึงยอดไหวไหม
phuak khao kamlang doen khuen khao yu kha tae mai nae chai wa cha doen pai thueng yot wai mai
They're walking up the mountain, but I'm not sure whether they can manage reaching the summit. (ordinary polite report, female speaker; actual progress versus projected capacity)
Omission and conversational commitment
When the demand is active, speakers can answer with ไหวครับ/ค่ะ or ไม่ไหวครับ/ค่ะ. A positive answer normally commits the speaker to being able to cope, but it does not itself say “yes, I agree to do it.” Context and a follow-up commitment settle willingness.
คืนนี้ทำงานต่อไหวไหมคะ
khuen ni tham ngan to wai mai kha
Can you manage working longer tonight? (ordinary polite workplace question, female speaker)
ไหวครับ เดี๋ยวผมทำส่วนนี้ให้เสร็จ
wai khrap diao phom tham suan ni hai set
I can manage. I'll finish this section. (ordinary polite reply, male speaker; capacity plus explicit commitment)
Register and lexical ไหว
Capacity ไหว is neutral and especially common in ordinary conversation. In formal medical, administrative, or technical prose, writers may prefer สามารถ...ได้ (formal to neutral), มีความพร้อม (formal), or a precise description of the limiting condition. Everyday workplace speech still naturally uses รับงานเพิ่มไหวไหม.
There is also lexical ไหว “move, shake, sway”: ม่านไหวตามลม “the curtain moves in the wind.” In that clause ไหว is the main predicate, not a capacity marker after an event.
ม่านไหวตามลมค่ะ ไม่ได้มีใครอยู่หลังม่าน
man wai tam lom kha mai dai mi khrai yu lang man
The curtain is moving in the wind; nobody is behind it. (ordinary polite speech, female speaker; lexical movement meaning)
Ordinary-polite dialogue
วันนี้รับงานเพิ่มอีกชิ้นไหวไหมคะ
wan ni rap ngan phoem ik chin wai mai kha
Can you handle one more task today? (ordinary polite workplace question, female speaker)
ถ้าส่งพรุ่งนี้เช้า ผมทำไหวครับ
tha song phrung ni chao phom tham wai khrap
If I can submit it tomorrow morning, I can manage it. (ordinary polite reply, male speaker; submission time defines the demand)
ได้ค่ะ ถ้าเริ่มไม่ไหวก็บอกฉันนะคะ
dai kha tha roem mai wai ko bok chan na kha
All right. Tell me if it starts becoming too much. (ordinary polite response, female speaker)
ขอบคุณครับ ตอนนี้ยังไหวอยู่
khopkhun khrap ton ni yang wai yu
Thank you. I'm still managing at the moment. (ordinary polite reply, male speaker)
Common Mistakes
1. Putting ไหว before the task
❌ ผมไหวยกกล่องนี้ครับ
Incorrect capacity order—the complete lifting event precedes ไหว.
✅ ผมยกกล่องนี้คนเดียวไหวครับ
phom yok klong ni khon diao wai khrap
I can manage lifting this box alone. (ordinary polite speech, male speaker)
2. Using ไหว for neutral learned know-how
❌ ฉันว่ายน้ำไหวค่ะ
Wrong for the intended learned-skill claim; ไหว evaluates whether swimming is manageable in a demanding situation.
✅ ฉันว่ายน้ำเป็นค่ะ แต่ยังว่ายไม่ไกล
chan wai nam pen kha tae yang wai mai klai
I know how to swim, but I still can't swim far. (ordinary polite speech, female speaker)
3. Using event denial for insufficient capacity
❌ งานเยอะมาก ฉันไม่ได้ทำคนเดียวค่ะ
Wrong for ‘I cannot manage it alone’; this primarily says that I did not do it alone.
✅ งานเยอะมาก ฉันทำคนเดียวไม่ไหวค่ะ
ngan yoe mak chan tham khon diao mai wai kha
There is too much work; I can't manage it alone. (ordinary polite workplace speech, female speaker)
4. Confusing capacity ไหว with lexical movement
❌ ต้นไม้ไหวแรงครับ
Wrong for the intended ‘the tree can withstand strong wind’; this naturally means that the tree sways strongly.
✅ ต้นไม้นี้ทนลมแรงได้ครับ
tonmai ni thon lom raeng dai khrap
This tree can withstand strong winds. (ordinary polite report, male speaker; practical capacity expressed with ได้)
Key Takeaways
- Place ไหว after the complete event or burden; negate it as event + ไม่ไหว.
- ไหว compares physical, mental, temporal, or situational resources with a specific demand.
- เป็น profiles learned know-how, ได้ practical possibility, and ไหว manageability under load.
- ไม่ไหวแล้ว often marks a newly crossed limit; ยังไหวอยู่ says capacity is still holding.
- Bare ไหว/ไม่ไหว is natural only when the demand is recoverable from the conversation.
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- ได้, เป็น, สามารถ, and ไหวA2 — Choose among Thai constructions for practical possibility, learned skill, general capacity, and manageable limits.
- Ability and Opportunity with ได้A2 — Place ได้ after an event to express practical ability or opportunity, and use word order to separate can-do meaning from realized events.
- Learned Skill with เป็นA2 — Use an activity followed by เป็น to express learned know-how, and separate skill from present opportunity or stamina.
- สามารถ in Neutral and Formal Ability StatementsA2 — Use สามารถ to state explicit capacity in professional, technical, and careful Thai, and contrast it with conversational postverbal ได้.
- Sentence-Final แล้ว and Change of StateA2 — Use sentence-final แล้ว to signal that a new situation now holds relative to an earlier state or expectation.
- Choosing ได้, เป็น, สามารถ, and ไหว for CanA2 — Choose a Thai ability construction by separating practical possibility, learned know-how, explicit capacity, and manageability.