Idioms are phrases in language that do not make literal sense but have understood meanings. Their origins are varied, with many coming from ancient literature or films and being quotations from writers like Shakespeare. Learning the backgrounds of idioms can help remember them. Idioms should be used appropriately and add richness to speech, though their grammar and vocabulary cannot be altered without losing meaning. Idioms can also be fun to use in writing to describe attitudes, behaviors, or draw attention to important points through imagery.