ㅎ is silent in 않, 찮. But 않, 찮 aren't used alone so you need to be aware of some rules. ㄱ+ㅎ=ㅋ, ㄷ+ㅎ=ㅌ, ㅂ+ㅎ=ㅍ, ㅈ+ㅎ=ㅊ 생각하다 > 생가카다 좋지 않다 > 조치 안타 좋지 않아 > 조치 아나 괜찮다 > 괜찬타 괜찮지가 않아 > 괜찬치가 아나

않다 = 아니하다 라는 줄인말 This is contraction For example: He doesn't go there

I think the syllable "ㅎ" as in "않" is bothering you, but it is pronounced exactly as "안". "않" itself is pronounced like "안", but it will make a difference when it comes to "않다". As in "않다", the syllable "ㅎ" affects the next word "다", and makes it pronounced like "타(ta)". let's see how it is pronounced 안다(i know sb or i know about sth) : /an da/ 않다(make sentences negative) : /an ta/ 안+ㅎ+다 = 안+타 it's just my two cents.

않(not) + 다 = be not or do not 않 is a negative. ex) She's not pretty. 그녀는 예쁘지 않다. Is it correct or not? sorry