Well.. He was the last one to test that day, so I did it fast. He has a line built in his ulti ("Silence" (4th GS line)) and CotS ("Curse you" (3rd CotS line)). Unlike with the other heroes, I didn't check his spell lines.
Yes, but the in-built ones don't sound like those. Actually, yeah... It makes it seem like if he's saying it, but he is in fact not. That's weird. Maybe it's even intentional that the real lines are unused? Or... Damn it, it's been almost a full moth since I've seen a live Silencer to be sure if I'm right.

Gotta bring my old self back in and play a Silencer game today to find out whether the in-built sounds are the same as the voice responses.