An embedded question is a question used as the content of a larger clause: ฉันไม่รู้ว่าเขาอยู่ไหน “I don't know where he is,” ช่วยตรวจดูว่าประตูล็อกหรือยัง “Please check whether the door is locked,” or เขาถามว่ารถออกกี่โมง “He asked what time the bus leaves.” The embedded material still contains an unresolved person, thing, place, time, quantity, reason, manner, or truth value.
The general ว่า-complement guide explains the clause boundary after speech and thought predicates; this page focuses on interrogative content inside that boundary.
English changes word order between Where is he? and I don't know where he is. Thai does not need that contrast because the direct question already keeps its interrogative in the answer slot. เขาอยู่ไหน stays เขาอยู่ไหน after ไม่รู้ว่า. Verbs do not backshift or conjugate; the larger predicate and context tell the listener whether the speaker is asking, reporting, wondering, or checking.
Direct and embedded content questions keep the same inner order
The embedding frame goes around a Thai question; it does not rebuild the question in English declarative order.
| Direct question | Embedding frame | Embedded question |
|---|---|---|
| เขาอยู่ไหน | ฉันไม่รู้ว่า... | ฉันไม่รู้ว่าเขาอยู่ไหน |
| ใครส่งไฟล์มา | ช่วยดูหน่อยว่า... | ช่วยดูหน่อยว่าใครส่งไฟล์มา |
| รถออกกี่โมง | พนักงานบอกหรือยังว่า... | พนักงานบอกหรือยังว่ารถออกกี่โมง |
| ต้องแก้ส่วนไหน | เขาถามว่า... | เขาถามว่าต้องแก้ส่วนไหน |
| ทำไมระบบหยุดทำงาน | ทีมกำลังตรวจสอบว่า... | ทีมกำลังตรวจสอบว่าทำไมระบบหยุดทำงาน |
ฉันยังไม่รู้ว่าเขาพักอยู่ที่ไหนค่ะ
chan yang mai ru wa khao phak yu thi nai kha
I still don't know where he is staying. (ordinary polite statement, female speaker; embedded location question)
ช่วยตรวจหน่อยครับว่าใครส่งไฟล์ฉบับนี้มา
chuai truat noi khrap wa khrai song fai chabap ni ma
Please check who sent this version of the file. (ordinary polite request, male speaker; embedded subject question)
หัวหน้าถามว่าต้องแก้รายงานส่วนไหนครับ
huana tham wa tong kae raingan suan nai khrap
The supervisor asked which part of the report needed revision. (ordinary polite report, male speaker; embedded selection question)
ทีมกำลังตรวจสอบว่าทำไมระบบถึงหยุดทำงานค่ะ
thim kamlang truat sop wa thammai rabop thueng yut tham ngan kha
The team is investigating why the system stopped working. (ordinary polite statement, female speaker; embedded reason question)
In each sentence, ว่า opens the embedded content. The wh-expression stays where it is interpreted inside that content. The final ครับ/ค่ะ belongs to the speaker's whole utterance, not to the person whose question is reported.
Embedded yes–no questions retain a choice marker
An embedded content question keeps ใคร, อะไร, ที่ไหน, เมื่อไร, and similar forms. An embedded polar question needs a device that preserves the positive–negative choice, commonly ไหม, หรือเปล่า, or หรือยัง according to meaning.
ผมไม่แน่ใจว่าร้านนี้รับบัตรไหมครับ
phom mai nae chai wa ran ni rap bat mai khrap
I'm not sure whether this shop accepts cards. (ordinary polite statement, male speaker; embedded neutral polar question)
ช่วยดูหน่อยค่ะว่าประตูหลังล็อกหรือยัง
chuai du noi kha wa pratu lang lok rue yang
Please check whether the back door has been locked yet. (ordinary polite request, female speaker; embedded change-of-state question)
ลูกค้าถามว่าสินค้ามาถึงหรือเปล่าค่ะ
luk kha tham wa sinkha ma thueng rue plao kha
The customer asked whether the product had arrived. (ordinary polite report, female speaker; embedded explicit alternative)
English whether is not a signal to remove Thai question marking. In ว่า...ไหม, ว่า marks the complement boundary while ไหม marks the unresolved truth value inside it. They perform different jobs.
The outer clause determines the utterance type
An embedded question does not automatically make the entire sentence a direct question. Compare three layers built around one schedule question:
รถรับส่งออกกี่โมงคะ
rot rap song ok ki mong kha
What time does the shuttle leave? (ordinary polite direct question, female speaker)
ฉันไม่รู้ว่ารถรับส่งออกกี่โมงค่ะ
chan mai ru wa rot rap song ok ki mong kha
I don't know what time the shuttle leaves. (ordinary polite statement, female speaker; embedded question)
คุณรู้ไหมครับว่ารถรับส่งออกกี่โมง
khun ru mai khrap wa rot rap song ok ki mong
Do you know what time the shuttle leaves? (ordinary polite matrix yes–no question, male speaker; embedded content question)
The first ends in female question คะ because it directly requests a time. The second ends in female statement ค่ะ because it asserts lack of knowledge. In the third, ไหมครับ belongs to outer คุณรู้ไหม; กี่โมง remains inside the content. Although the literal matrix question asks “Do you know?”, cooperative conversation usually favors giving the departure time rather than answering only รู้ครับ.
Indirect polite inquiries
Thai often uses ไม่ทราบว่า... “I do not know / may I ask...” to package a respectful inquiry. Grammatically, ไม่ทราบ is the outer predicate; pragmatically, the whole utterance recruits an answer, so a female speaker normally ends it in คะ.
ไม่ทราบว่าห้องอบรมอยู่ชั้นไหนคะ
mai sap wa hong oprom yu chan nai kha
May I ask which floor the training room is on? (formal-polite indirect inquiry, female speaker; I omitted)
ไม่ทราบว่าต้องยื่นเอกสารภายในวันไหนครับ
mai sap wa tong yuen ekkasan phainai wan nai khrap
May I ask by which day the documents must be submitted? (formal-polite indirect inquiry, male speaker)
This is not a contradiction with statement ค่ะ. ฉันไม่ทราบว่า...ค่ะ can be a report of ignorance, perhaps explaining a delay. Standalone ไม่ทราบว่า...คะ conventionally functions as an indirect question. Punctuation alone cannot determine the social action.
ว่า can be omitted, but the boundary must stay clear
In conversation, ว่า may be absent after frequent predicates when prosody and participant structure make the boundary recoverable: ไม่รู้เขาไปไหน “I don't know where he went.” This is (informal conversational) and should not become a rule to delete ว่า everywhere.
ยังไม่รู้เลยค่ะว่าเขาจะกลับเมื่อไร
yang mai ru loei kha wa khao cha klap muearai
I still have no idea when he will return. (ordinary polite conversation, female speaker; ว่า-clause follows an intonational break)
Here the polite particle can close the framing comment before the content is added as an afterthought. In careful writing, ยังไม่รู้ว่าเขาจะกลับเมื่อไรค่ะ keeps the clause boundary transparent. With บอก + person, retaining ว่า is especially helpful because the noun before it is otherwise readily parsed as the addressee rather than the embedded subject.
Time, aspect, and viewpoint do not backshift automatically
Thai does not change an embedded verb merely because the outer speech or thought occurred earlier. Each clause carries its own temporal cues.
เมื่อเช้าเขาถามว่าพรุ่งนี้เราจะเริ่มงานกี่โมงครับ
muea chao khao tham wa phrung ni rao cha roem ngan ki mong khrap
This morning he asked what time we would start work tomorrow. (ordinary polite report, male speaker; outer past and inner prospective time stated separately)
The outer เมื่อเช้า locates the asking. Inner พรุ่งนี้ and จะ present the work as prospective from the relevant viewpoint. Thai does not create a past form of ถาม or a conditional form of เริ่ม. If words like “today” or “tomorrow” would be ambiguous after time has passed, speakers clarify with a date or วันรุ่งขึ้น (neutral-to-formal) “the following day,” rather than applying mechanical tense agreement.
Participant reference inside the embedded question
An omitted subject is interpreted from discourse. If the embedded actor changes, name that actor. Compare นิดถามว่าจะกลับเมื่อไร: without more context, zero after ว่า is readily linked to Nit, so the sentence asks when Nit herself would return. To report that Nit asked when her manager would return, say นิดถามว่าผู้จัดการจะกลับเมื่อไร.
คุณนิดถามว่าผู้จัดการจะอนุมัติงบเมื่อไรค่ะ
khun nit tham wa phu chatkan cha anumat ngop muearai kha
Khun Nit asked when the manager would approve the budget. (ordinary polite report, female speaker; embedded actor stated to prevent a reference error)
The final ค่ะ reflects the current female reporter, not Nit or the manager. Names, titles, pronouns, and zero handle reference; polite particles handle the current interaction.
Ordinary-polite dialogue
A female colleague and male colleague clarify a delivery schedule.
คุณรู้ไหมคะว่าของจะมาถึงวันไหน
khun ru mai kha wa khong cha ma thueng wan nai
Do you know which day the delivery will arrive? (ordinary polite matrix question, female speaker)
ยังไม่รู้ครับ แต่ผมถามบริษัทขนส่งแล้ว
yang mai ru khrap tae phom tham borisat khon song laeo
Not yet, but I've asked the shipping company. (ordinary polite answer, male speaker)
ได้ถามไหมคะว่าเขาจะยืนยันเวลาเมื่อไร
dai tham mai kha wa khao cha yuenyan wela muearai
Did you ask when they would confirm the time? (ordinary polite matrix yes–no question, female speaker)
ถามแล้วครับ เขาบอกว่าจะตอบภายในวันนี้
tham laeo khrap khao bok wa cha top phainai wan ni
Yes. They said they would answer by the end of today. (ordinary polite response, male speaker)
The matrix questions use ไหมคะ; the embedded questions use วันไหน and เมื่อไร without additional ไหม. The answers repeat only as much outer predicate as needed.
Common Mistakes
1. Applying English embedded-question inversion
❌ ฉันไม่รู้ว่าที่ไหนเขาอยู่ค่ะ
Incorrect English-influenced order—ที่ไหน remains after the locative predicate inside the embedded question.
✅ ฉันไม่รู้ว่าเขาอยู่ที่ไหนค่ะ
chan mai ru wa khao yu thi nai kha
I don't know where he is. (ordinary polite statement, female speaker)
2. Removing the polar marker after ว่า
❌ ผมไม่แน่ใจว่าร้านรับบัตรครับ
Wrong for the intended ‘whether’ meaning—without ไหม or another alternative frame, the complement reads as a proposition.
✅ ผมไม่แน่ใจว่าร้านรับบัตรไหมครับ
phom mai nae chai wa ran rap bat mai khrap
I'm not sure whether the shop accepts cards. (ordinary polite statement, male speaker)
3. Adding ไหม to a content question
❌ เขาถามว่าต้องส่งเอกสารที่ไหนไหมค่ะ
Incorrect double marking for an embedded location question—ที่ไหน already requests the missing place.
✅ เขาถามว่าต้องส่งเอกสารที่ไหนค่ะ
khao tham wa tong song ekkasan thi nai kha
She asked where the documents had to be sent. (ordinary polite report, female speaker)
4. Choosing คะ merely because an embedded question is present
❌ ฉันไม่รู้ว่าใครถือกุญแจคะ
Incorrect for the intended female statement—the whole utterance reports not knowing, so it takes ค่ะ.
✅ ฉันไม่รู้ว่าใครถือกุญแจค่ะ
chan mai ru wa khrai thue kunchae kha
I don't know who has the key. (ordinary polite statement, female speaker)
5. Leaving a changed embedded actor implicit
❌ คุณนิดถามว่าจะกลับเมื่อไรค่ะ
Ambiguous for the intended ‘Nit asked when the manager would return’; zero is readily understood as Nit.
✅ คุณนิดถามว่าผู้จัดการจะกลับเมื่อไรค่ะ
khun nit tham wa phu chatkan cha klap muearai kha
Khun Nit asked when the manager would return. (ordinary polite report, female speaker)
Key Takeaways
- Thai keeps the inner question order unchanged: เขาอยู่ไหน → ไม่รู้ว่าเขาอยู่ไหน.
- Use a wh-expression for embedded content and ไหม/หรือเปล่า/หรือยัง for an unresolved polar choice.
- The outer clause determines whether the whole turn is a statement, direct question, indirect inquiry, request, or report.
- Final ครับ/ค่ะ/คะ reflects the current speaker and whole-turn action, not the quoted speaker or the mere presence of a wh-word.
- State a changed embedded actor, and locate outer and inner time separately; Thai has no obligatory inversion or reported-speech backshift.
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- Wh-Words Stay in Their Ordinary SlotA2 — Form Thai content questions by placing ใคร, อะไร, ไหน, เมื่อไร, and related expressions where the requested answer would ordinarily appear.
- Yes–No Questions with ไหมA1 — Form neutral Thai polar questions by keeping declarative order and adding clause-final ไหม before the appropriate polite particle.
- Speech and Thought Frames with ว่าB2 — Introduce reported statements, thoughts, and questions with ว่า while tracking addressees, viewpoint, omission, and negation scope.
- ว่า Clauses after Speech and ThoughtB1 — Use ว่า to introduce the proposition spoken, thought, believed, or reported while keeping participant roles, viewpoint, and negation scope clear.
- ใคร, อะไร, and Indefinite ReadingsB1 — Interpret ใคร and อะไร as questions, negative-polarity indefinites, free-choice forms, or unspecified participants from their grammatical environment.
- Predicate Ellipsis and Short AnswersB2 — Build natural Thai short answers by retaining the focused verb, polarity, aspect, modal, or fragment while recovering the rest from discourse.