I talk to mine too. And although I know they can't hear me, I do believe it has a calming effect that translates to them as comfort. I talk to them as if they're human adults, and I believe that calm in my voice resonates with them. That calm helps to develop the "trust" that @zina10 was talking about.
Calm, deliberate movements and demeanor go a long way in earning that mutual trust. I am completely calm and comfortable handling my snakes, and I can see the calm in them as well. However, if somebody else is handling them and they don't have that same calm demeanor I do, I can see the difference in the snake too.
Take your time, and develop a mutual trust. It'll come, but when the time is right. As discussed previously, he needs proper husbandry and time right now. And you've already showed that you understand this and are on board. After he sheds give it a few more weeks and start shirt and sweet handling sessions. It'll come....