The occipital lobe is responsible for vision, not speech. If your speech was to be affected by a head injury, it would have had to be a stroke or lesion to the motor planning area in the parietal lobe, on the top of your head. And I can tell you with 100% certainty that there is zero research showing that an issue with tonsils would affect stuttering. Consonants are difficult for me to pronounce too, and I always block on them, but I have no tonsil issues. You don't have to take my word for it, but I'm just trying to help given that I have 5 years of experience studying speech and language disorders at the collegiate level. Have a good night, friend.