Because Vader is Anakin?

His voice was coming thru the broken area of the mask not the vocoder.

Yah but his vocal cords don’t work without the mask

As far as I know he could still speak, it was just painful and difficult. In full blown dark side mode as he was in that duel perhaps he could get out those words.

^^Then they wouldn’t work with the mask either. Also, ROTJ disproves that.

^ Exactly. If anything he's much more chatty with his mask off.

Because Vader is a gigachad.

(Rare footage of Darth Vader removing his suit in a Star Wars Rebels deleted scene).

Because it was the Anakin side who side Ahsoka and to the show her that he has fully changed and became who he is. Plus I thought it was neat merging Matt and James's voice together

The scorched vocal cords thing is a bit sus to me. I mean he yells at Obi-wan after being burned on the lava beach. Haven’t we all seen the memes? And then he’s groaning like Frankenstein throughout his Darth Vader conversion procedure. That’s all vocal cords…

^^ I wouldn't say his "Anakin side," but instead say how it was most likely meant to represent how despite everything he's done as Darth Vader, he's still a human being, manipulated by the dark side.