So, the " shm" sound means I don't care about that.

所以，“嘘”的声音意味着我不关心那个。

The " shm" sound is added to a word to make fun of it, and to show that you don't really care about that particular thing.

“shm” 音被加到一个词上来取笑它，并表明你并不真正关心那件事。

The " shm" sound in a Yiddish word is often used to make fun of people, so English speakers have sort of taken that and adapted it to using it in English.

意第绪语单词中的“shm” 音经常被用来取笑别人，因此说英语的人已经接受了它并将其改编为英语。