How to say “I don't know” in Thai

Mai ru: the everyday "I don't know"

รู้rúu means to know, and ไม่รู้mâi rúu is "don't know". With friends it stands alone; with strangers, add your particle: ไม่รู้ครับmâi rúu kráp or ไม่รู้ค่ะmâi rúu kâ. To say what you don't know, add ว่าwâa ("that, whether") and the question: ไม่รู้ว่าอยู่ที่ไหนmâi rúu wâa yùu tîi-nǎi, "I don't know where it is".

Mai sap: the polite one

Thai has polite versions of some everyday words, and "know" is one of them. ทราบsâap is what staff, officials and well-mannered people use with customers, elders and bosses: a receptionist will say ไม่ทราบค่ะmâi sâap kâ, and a bank will write ทราบแล้วsâap láew ("noted"). Using ไม่ทราบmâi sâap with your partner's parents or your landlord sounds well brought up. It works like ทานtaan, the polite word for "eat".

A little script curiosity: ทราบsâap is spelled with the letters for t and r together, but that pair is read as an s.

Knowing facts vs knowing people

Thai splits "know" in two, a bit like French savoir and connaître. รู้rúu is knowing a fact; รู้จักrúu-jàk is knowing a person, a place or a brand. So รู้จักร้านนี้ไหมrúu-jàk ráan níi mǎi is "do you know this restaurant?", and ไม่รู้จักmâi rúu-jàk is "never heard of it" or "I don't know them".

Asking for directions

Sometimes a kind stranger would rather point you somewhere than disappoint you with "I don't know". If directions matter, ask a second person, or go to the people who really know the area: security guards, motorbike-taxi riders and 7-Eleven staff.

Common mistakes

• Using รู้rúu for people: "I don't know him" is ไม่รู้จักเขาmâi rúu-jàk kǎo, not "mâi rúu kǎo".
• A bare ไม่รู้mâi rúu to a stranger. Without a particle it can sound curt; add ครับkráp or ค่ะkâ and a little apologetic smile.
• Mixing up ไม่รู้mâi rúu (I don't know) and ไม่รู้เรื่องmâi rúu-rûeang (I can't make sense of it).

Pronunciation

รู้rúu is high and long; ทราบsâap falls, ending in a p you don't release; แน่ใจnâe-jai falls then stays level.