This question has already been answered: http://www.enotes.com/macbeth/q-and-a/using-act-5-scene-1-what-ways-has-lady-macbeth-302740
Lady Macbeth's language in this scene betrays her troubled mind in many ways. Her speech in previous acts has been eloquent and smooth. In Act 1 Scene 4, she makes a speech to Duncan. In this speech, Lady Macbeth makes use of metaphor (Duncan's honor is "deep and broad"), metonymy (he honors "our house," meaning the Macbeths themselves).Her syntax is complex but the rhythm of her speech remains smooth and flowing, in the iambic pentameter used by noble characters in Shakespearean plays. There is stark contrast when she talks in her sleep in Act 5. This speech, Lady Macbeth's language is choppy, jumping from idea to idea as her state of mind changes. Her sentences are short and unpolished, reflecting a mind too disturbed to speak eloquently. Although she spoke in iambic pentameter before, she now speaks in prose—thus falling from the noble to the prosaic. Lady Macbeth's dissolution is swift. As Macbeth's power grows, indeed, Lady Macbeth's has decreased. She began the play as a remorseless, influential voice capable of sweet-talking Duncan and of making Macbeth do her bidding. She has dwindled to a mumbling sleepwalker, capable only of a mad and rambling speech. Whereas even the relatively unimportant Lady Macduff has a stirring death scene, Lady Macbeth dies offstage.
Lady Macbeth's behavior can reveal truths about Lady Macbeth, can underscore flaws in or beauties of her nature, and can enhance philosophical, religious, historical, cultural, or interpersonal themes; however, Lady Macbeth's behavior cannot affect the way the audience sees her. Maybe this analogy can help clarify what I'm trying to say: I can pay attention all day to what my sister Mary does, but no matter how well I understand her and her behavior, I cannot know how her behavior affects the way my other sister, Sandy, sees her. Sure I can guess, but that guess would say more about the way I see Sandy than about the way Sandy sees Mary.