Breakdown of ทำไม เขา ยิ้ม อยู่ คะ
เขา
he, she, they
คะ
female question particle / polite particle (female)
ทำไม
why
อยู่
continuous aspect marker (still doing)
Questions & Answers about ทำไม เขา ยิ้ม อยู่ คะ
Why do we use อยู่ here instead of กำลัง for an ongoing action?
Both are used for continuous actions, but they go in different places: กำลัง goes before the verb, and อยู่ goes after. For lingering physical states like smiling (ยิ้ม), sitting, or standing, Thai speakers very commonly use อยู่ on its own right after the verb.
Is it okay to put ทำไม (why) at the end of this sentence instead of the beginning?
Yes! You will often hear Thai people put ทำไม at the end of a sentence. เขายิ้มอยู่ทำไมคะ is perfectly correct, though putting it at the end can sometimes sound a little more direct or demanding, like asking 'What is he smiling for?'.
Does คะ at the end mean that เขา has to be translated as 'she'?
No, the polite particle คะ only tells us that the person asking the question is female. The pronoun เขา can mean he, she, or they, regardless of which polite particle ends the sentence.
I've heard เขา pronounced with a high tone in real life, but the spelling dictates a rising tone. Which is correct here?
In formal writing, เขา follows the rules for a rising tone. However, in everyday spoken Thai, it is almost always pronounced with a high tone (as if it were spelled เค้า). It is best to use the high tone when speaking this sentence so you sound more natural.