(especially his plays) also feature extensive wordplay in which double entendres and rhetorical flourishes are repeatedly used. Humour is a key element in all of Shakespeare's plays. Although a large amount of his comical talent is evident in his comedies, some of the most entertaining scenes and characters are found in tragedies such as Hamlet and histories such as Henry IV, Part 1. Shakespeare's humour was largely influenced by Plautus. Soliloquies in plays Shakespeare's plays are also notable for their use of soliloquies, in which a character, apparently alone within the context of the play, makes a speech so that the audience may understand the character's inner motivations and conflict. In his book Shakespeare and the History of Soliloquies, James Hirsh defines the convention of a Shakespearean soliloquy in early modern drama. He argues that when a person on the stage speaks to himself or herself, they are characters in a fiction speaking in character; this is an occasion of self-address. Furthermore, Hirsh points out that Shakespearean soliloquies and "asides" are audible in the fiction of the play, bound to be overheard by any other character in the scene unless certain elements confirm that the speech is protected. Therefore, a Renaissance playgoer who was familiar with this dramatic convention would have been alert to Hamlet's expectation that his soliloquy be overheard by the other characters in the scene. Moreover, Hirsh asserts that in soliloquies in other Shakespearean plays, the speaker is entirely in character within the play's fiction. Saying that addressing the audience was outmoded by the time Shakespeare was alive, he "acknowledges few occasions when a Shakespearean speech might involve the audience in recognising the simultaneous reality of the stage and the world the stage is representing". Other than 29 speeches delivered by choruses or characters who revert to that condition as epilogues "Hirsh recognizes only three instances of audience address in Shakespeare's plays, 'all in very early comedies, in which audience address is introduced specifically to ridicule the practice as antiquated and amateurish.'" Source material of the plays As was common in the period, Shakespeare based many of his plays on the work of other playwrights and recycled older stories and historical material. His dependence on earlier sources was a natural consequence of the speed at which playwrights of his era wrote; in addition, plays based on already popular stories appear to have been seen as more likely