Shakespeare revolutionized literature and language through his plays. His works expanded the use of characterization, genre, plot, and language. Through writing Romeo and Juliet, he allowed people to accept the romance genre as a worthy topic for tragedy. His works have influenced later poets and novelists such as Charles Dickens, Thomas Hardy, and Herman Melville. Shakespeare's play, Hamlet, even inspired Sigmund Freud's theories about human nature. The language he used in his work has heavily influenced modern English and phrases he invented are still commonly used today. He invented over 1700 words by adding prefixes and suffixes.