What is the significance of Gregor’s inability to speak in "The Metamorphosis" by Franz Kafka?
Unfortunately your original posting contained two questions; the other was a little more vague, so I kept this one. Please post the other question again when you have the opportunity, and I am certain it will be answered to your satisfaction.
One morning Gregor Samsa discovers he has been transformed into a gigantic bug. When the story begins, he is lying helplessly on his back, a fitting image for what happens to him the rest of the story. He is helpless and cannot speak, at least in a way that his family and others can understand, and his inability to articulate his needs eventually kills him.
Before today, Gregor worked relentlessly both to pay off his parents' debt and to ensure that his parents and sister could live a comfortable life without having to work. Though he was good at his job, he constantly experienced the "curse of travelling, worries about making train connections, bad and irregular food, contact with different people all the time so that you can never get to know anyone or become friendly with them." All of these things wore on him, but he never articulated them. He sees "other travelling salesmen live a life of luxury" and considers asking his boss for a less strenuous job, but he is again unable to articulate his desire.
Since his transformation, nothing has changed.
Gregor was shocked when he heard his own voice answering, it could hardly be recognised as the voice he had had before. As if from deep inside him, there was a painful and uncontrollable squeaking mixed in with it, the words could be made out at first but then there was a sort of echo which made them unclear, leaving the hearer unsure whether he had heard properly or not.
When his mother finally calls in to him and asks if he is okay (only because he is late for work, of course), Gregor is unable to tell her what is wrong. When she faints in horror at the sight of him, Gregor has no words to comfort her. When his sister calls, he is afraid to answer, not "daring to raise his voice loud enough for his sister to hear." When she tries to bring him food, he is unable to explain that what he once loved is now unpalatable to him. When Gregor thinks his father wants to scold him, as he has always tended to do, Gregor does not run away; instead he tries to make it easy for his father to reprimand him.
Gregor he ran up to his father, stopped when his father stopped, scurried forwards again when he moved, even slightly. In this way they went round the room several times without anything decisive happening, without even giving the impression of a chase as everything went so slowly. Gregor remained all this time on the floor, largely because he feared his father might see it as especially provoking if he fled onto the wall or ceiling.
Because Gregor is not able to tell his father that he is simply trying to make things easier (a constant theme in Gregor's life), his father interprets his actions as aggressive and pelts him with apples. One of them lodges in Gregor's back and seriously wounds Gregor, a wound which undoubtedly leads directly to his death.
Gregor's inability to communicate and be anything but an unquestioning, obedient drudge carries over into his life as a bug. That is not a coincidence. Kafka turned Gregor into the creature which most resembled his real life--in this case a bug which no one wants and which is unable to communicate effectively with anyone he cares for. He lives a lonely, silent life and dies the same way.