Shouldn't Sion have a speech impediment?
https://www.mobafire.com/images/avatars/sion-classic.png
His lower jaw is not only prosthetic, but it was never designed as such (it's a crown). I'll accept that this crown-jaw is properly attached to his TMJ so he can at least open and close his mouth in some rudimentary fashion, but there's no way it's usable for producing anything close to what he needs for his voice lines, particularly "F" and "V" sounds, which heavily rely on the lower lip.
"'orget the 'aces o' the slain!"