Anyone who has ever learned a new language knows that the hardest part is learning how to use expressions, or idioms, correctly. Idioms are not easily understood by the words they use. For example, if an English learner hears, "This jacket costs an arm and a leg," he or she can become very confused. Or if they hear a weatherperson say, "It's raining cats and dogs," they may look outside expecting to see cats and dogs falling from the sky. However,...