Apparently I've started speaking in a rather dull tone (Speaking in any other tone causes my voice to crack) and it drives my father crazy. I can not more then a sentence to him or he gets annoyed by voice and tells me to go away. My mother has no problem with my voice and my grandfather is pleased by it. It is just my father. I want to trust him, but if issues like this prevent me from even speaking to him then I see no point in trying.
The problem your father has with your voice seems a bit superficial, are you sure there are no underlying issues that bother him? I would suggest to sit together with him and your mother and discuss what is exactly bothering him, so you can both get past this.
That seems like a very weird reason for your father not to talk to you. It may be worth talking to your mom about the problem and see if she can help you somehow.
Why would your father be like that? it makes no sense. Has anything been bothering your father lately that would result him in taking it out on you? have you noticed anything different or do you think it is directly because of your voice? be upfront and honest with him, and tell him that it hurts you...he is your father after all, so i am very sorry that he chooses to act that way!