Yes, he will eventually gain the ability to speak at some point, and iirc, the LN says that his voice is quite deep and manly.
It's been 3 months since I've read the LN so don't take my word for it
Edit: I looked back at the LN and apparently his voice is so manly that even Jin Woo cannot stand how manly it is
I'm pretty sure most of the LN readers can agree with me on this, but they've skipped way too much dialouge and scenes from the LN which, even though it wasn't really important in the story, still proved to be interesting sometimes, or even invoked some emotion to the readers.
Yes, i'm sure we can all agree that the art here is absolutely fantastic, but that doesn't amount to the fact that so much of the LN has been, sometimes, completely ignored or skipped, making those who read the LN, like me, honestly disappointed.
Of course, this means we'll manage to get to the juicier stuff sooner, but at what cost?