A few years back, I suffered a serious head injury while playing on the park. I suffered some brain damage from it (traumatic amnesia, some permanently damaged brain cells) and also some of my speech is slurred while pronouncing certain words, and my voice sounds extremely nasally while singing these words especially. There is also some permanently scarred tissue around my nasal cavity (from serious cold viruses, etc...)

Is there anyway I can have complete control of my voice? How should I pronounce these words, and how should I breathe while I sing? I'm also worried I may have either damaged my singing voice while trying to sing raspy (I think raspy singing is cool) however I can control the rasp like turn it on and off... but I don't think that's healthy, is it?How do I heal my voice if it's damaged?