Cool means good, the american youngsters created it. It is colloquial English, even though it is widly spread all over the world. But, it is not in the dictionary.

here in our country, we regard those who speak english as "cool" since before, it is most spoken by the "upscale" person (especially those with higher learnings) and/or politicians only. So, everybody will be amazed when they hear you speak english. In other words, english-speaking is an indication of one's status in life.... but that was BEFORE.... I think this is what makes english such a "cool" language. :)

I like its pronounciation and tones.

There is a grammar correction on your question I guess , if you don't mind ? "What makes ....."

i think "cool"is just close to "ku( 酷)"in chinese, but i feel uncertain how it comes in english