Okay, I'm VERY late to this, so you likely won't see this reply (Unless you for some reason followed the thread?) But to anyone seeing this after the original poster said this;
편지 is a written letter one may receive in the mail whilst 글자 is like an alphabetical letter
Can anyone explain the difference between the negative endings "verb지 않다" vs. "안 verb"? Do the two have different meanings or uses?
Technically they are different, but for all non-academical purposes, you can say they are the same.
Does this mean right as in correct? I'm inclined to think so, as the sentence would otherwise be a bit confusing but...