One of the hardest things to learn in any language is the colloquialisms. Old words and phrases that are commonly used among native speakers but have no real relevance to modern language. In English, these are known as idioms. They can be widely used or constrained to certain geographical areas. They can make sense or be completely inane. What they have in common, however, is that native speakers will understand the idea behind the idiom where English learners will not.