In English and French you can turn a statement into a question with your voice alone: 'You're hungry?' rises at the end. Thai cannot do that, because the pitch of the last word already belongs to the word. Raise a falling word and you have said a different word, or nothing at all.
Thai asks with a word instead. ไหม at the end of a sentence makes it a yes or no question, and the words before it keep exactly the tones they had in the statement.
- หิวhǐw
hungry
rising, as a statement
- หิวไหมhǐw mǎj
are you hungry?
หิว keeps its own rise; ไหม does the asking
- ไม่หิวmâj hǐw
not hungry
ไม่ falls, even at the start of an answer
The particle trap
The words most often hit are the politeness particles, because they sit at the end of every sentence, which is exactly where your native intonation acts. ค่ะ falls on a statement and คะ is high on a question. Lift the end of a statement and ค่ะ comes out as คะ, which reads as a question nobody asked.
- ค่ะkʰâ
polite, statement (female)
falling, even when you feel like rising
- คะkʰá
polite, question (female)
high
How to practise it
Record a statement and the same statement with ไหม, then compare the pitch of the shared words. They should match. If the question version climbs before ไหม, your native intonation is doing the asking, and the Mouth drill in the tone dojo will show it.