[kuronekoaus]

All these examples of weird English usage are generally more slang or informal. As to making the language more difficult to learn, I'd say only if you wanted to pick up on absolutely everything, which with a foreign language or advanced lanuage usage you might not exactly need.

But then again, some understanding of such examples can come down to tone of voice, facial expression and gestures, as with any other strange phrases in any language.

Edit: I was looking at the expressions such as 'wise guy'. The other things are so uncommon (such as plural of BOOTH) that they're... slightly reduntant? Lol