Section 13 — Language of proceedings and interpreters
Statutory text (Thai original)
การสอบสวน ไต่สวนมูลฟ้อง หรือพิจารณา ให้ใช้ภาษาไทย แต่ถ้ามีความจำเป็นต้องแปลภาษาไทยท้องถิ่นหรือภาษาถิ่นหรือภาษาต่างประเทศเป็นภาษาไทยหรือต้องแปลภาษาไทยเป็นภาษาไทยท้องถิ่นหรือภาษาถิ่นหรือภาษาต่างประเทศให้ใช้ล่ามแปลในกรณีที่ผู้เสียหาย ผู้ต้องหา จำเลย
หรือพยานไม่สามารถพูดหรือเข้าใจภาษาไทยหรือสามารถพูดหรือเข้าใจเฉพาะภาษาไทยท้องถิ่นหรือภาษาถิ่น
และไม่มีล่าม ให้พนักงานสอบสวนพนักงานอัยการหรือศาลจัดหาล่ามให้โดยมิชักช้าในกรณีที่ผู้เสียหาย ผู้ต้องหา จำเลย
หรือพยานไม่สามารถพูดหรือได้ยิน หรือสื่อความหมายได้และไม่มีล่ามภาษามือ
ให้พนักงานสอบสวน พนักงานอัยการ หรือศาล จัดหาล่ามภาษามือให้หรือจัดให้ถาม ตอบ
หรือสื่อความหมายโดยวิธีอื่นที่เห็นสมควรเมื่อมีล่ามแปลคำให้การ คำพยานหรืออื่น ๆ
ล่ามต้องแปลให้ถูกต้อง ล่ามต้องสาบานหรือปฏิญาณตนว่าจะทำหน้าที่โดยสุจริตใจ
จะไม่เพิ่มเติมหรือตัดทอนสิ่งที่แปลให้ล่ามลงลายมือชื่อในคำแปลนั้นให้พนักงานสอบสวนพนักงานอัยการ หรือศาลสั่งจ่ายค่าป่วยการ ค่าพาหนะเดินทางและค่าเช่าที่พักแก่ล่ามที่จัดหาให้ตามมาตรานี้ตามระเบียบที่สำนักงานตำรวจแห่งชาติ กระทรวงมหาดไทย กระทรวงยุติธรรม สำนักงานอัยการสูงสุด หรือสำนักงานศาลยุติธรรม แล้วแต่กรณี กำหนดโดยได้รับความเห็นชอบจากกระทรวงการคลัง
English translation
An inquiry, preliminary examination or trial shall be conducted in the Thai language. But where it is necessary to translate a local Thai dialect, a regional language or a foreign language into Thai, or to translate Thai into a local Thai dialect, a regional language or a foreign language, an interpreter shall be used. Where the injured person, alleged offender, defendant or a witness cannot speak or understand Thai, or can speak or understand only a local Thai dialect or a regional language, and there is no interpreter, the inquiry official, public prosecutor or Court shall provide an interpreter without delay. Where the injured person, alleged offender, defendant or a witness cannot speak, hear, or communicate, and there is no sign-language interpreter, the inquiry official, public prosecutor or Court shall provide a sign-language interpreter, or arrange for questions, answers or communication to be made by another appropriate method. When an interpreter interprets statements, testimony or other matters, the interpreter must interpret correctly. The interpreter must take an oath or affirmation that he will perform his duty in good faith and will not add to or omit from what is interpreted, and the interpreter shall sign the interpretation. The inquiry official, public prosecutor or Court shall order payment of an allowance, travel expenses and accommodation expenses to the interpreter provided under this Section, in accordance with the regulations prescribed by the Royal Thai Police, the Ministry of Interior, the Ministry of Justice, the Office of the Attorney-General or the Office of the Judiciary, as the case may be, with the approval of the Ministry of Finance.
This English translation is provided for reference only and has not yet been firm-verified — always rely on the Thai original.
Firm annotation
Section 13 secures the fair-trial right to understand and be understood in criminal proceedings. It covers foreign languages, local dialects, and sign language, and obliges the inquiry official, prosecutor or court to supply an interpreter without delay when needed. The interpreter must translate correctly, take an oath and sign the interpretation; the Supreme Court has held that the interpreter must be a neutral person, not the investigating officer, prosecutor or judge conducting the matter, and that testimony taken through an interpreter who did not take the oath was not in compliance with this Section. Whether an interpreter is even necessary is judged case by case, so where a defendant genuinely understood Thai, none is required.
Why this matters in practice
If you or a witness cannot follow Thai, Section 13 entitles you to an interpreter, and the court or investigators must arrange one without delay, at state expense. Insist that the interpreter be an independent person and be sworn, because testimony taken through an unsworn or interested interpreter can be challenged. For non-Thai speakers facing court, understanding what to expect in a Thai court helps you prepare.
Supreme Court decisions interpreting this section
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Supreme Court Judgment No. 1351/2558 (2015)
No interpreter is required under Section 13 paragraph one where the defendant genuinely understood Thai and his confession reflected his true intention; the proceedings are lawful.
The Court held that the defendant's guilty plea reflected his true intention and did not arise from any failure to understand Thai. There was therefore no necessity to use an interpreter under Section 13 paragraph one, and the proceedings on the day his plea was taken were lawful.
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Supreme Court Judgment No. 10449/2556 (2013)
Where foreign-language witnesses testify through an interpreter, the failure of that interpreter to take the oath raises non-compliance with Section 13 in the taking of their testimony.
The foreign victims could not speak or understand Thai and testified through an interpreter, as shown by an interpreter's signature on their recorded depositions. The issue was whether their testimony was lawfully taken, the Court of Appeal having found it improper under Section 13 because the interpreter had not been sworn.
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Supreme Court Judgment No. 18538/2555 (2012)
Under Section 13, the interpreter may be any competent person but must not be the investigating officer, prosecutor or court conducting the inquiry or questioning, so an interested police officer serving as interpreter is improper.
The defendant challenged the use of a police officer with an interest in the case as interpreter for foreign witnesses at the inquiry and before trial. The Court read Section 13 to mean the interpreter may be any capable person but must not be the investigator, prosecutor or judge conducting the matter, so an interested officer was not a proper interpreter.
Curated decisions with case numbers verified against the Supreme Court database. English renderings are the firm's editorial translation for study.
Frequently asked questions
Do I get an interpreter in a Thai criminal case if I do not speak Thai?
Yes. Under Section 13, if a party or witness cannot speak or understand Thai and there is no interpreter, the inquiry official, prosecutor or court must provide one without delay.
Does the interpreter have to take an oath?
Yes. Section 13 requires the interpreter to translate correctly, take an oath or affirmation to act in good faith, and sign the interpretation; testimony through an unsworn interpreter may be invalid.
Can a police officer act as interpreter?
The Supreme Court has held that the interpreter must be a neutral person, not the investigating officer, prosecutor or judge handling the matter.
Is there sign-language support?
Yes. Section 13 requires a sign-language interpreter, or another appropriate method, for a person who cannot speak, hear or communicate.