I have been a regular on the 11th floor at Dana Farber on Jimmy Fund way since 2003, so I know that you are in great hands. Don't worry, they will do their absolute best and hopefully they won't find the cancer is so entrenched that they can get clean margins without too much impact. I know they like to warn us that speech may be hurt, but "may" is the operative word (and while they warned me, my speech is fine).
Neck dissection is quite probably part of the protocol, so be prepared for a scar on your neck. Mine is across the Adam's apple. If I were in a position to ask the surgeon for a favor I would ask to put the line below the apple, more along the natural fold line (but there may be a good reason why they can't). You should rest assured you have the right team on your side. Give us an update next month.