Hmmm.... personally, I think he can talk but he just doesn't want to and/or can't. In my head canon, Le Mime is tied to the 'Magical Mime' code, which is to never talk while being a magical mime. If he did talk, his magical mime ability will be less powerful or will completely disappear the more he talks.
I like a lot of your stuff thought I rarely comment.
I love your work and wish I could do just as well. However, I am curious.. Most of the stuff you do on here, what medium is it? I see a lot of pencil and coloured pencil work. I was wondering if the coloured pencil work was done on tablet or otherwise?