The below voices go unused in the game, but can be heard in the sound test:

Akuma: "Gouzanku"

Akuma's first super art is the messatsu gou hadou, however he can also do this move in the air, the air version's name is the tenma gouzanku. A voice clip was recorded for part of the move, but it never gets used.

Announcer: "New Generation"

This was used in the previous game, but goes unused in this one because of the new subtitle.

Unknown: "1P Win!", "2P Win!", "Judgment!"

These voice clips are located in the sound test close to some related to the bonus game. I think originally, the plan was that you could play the bonus game with 2 players, and these voice clips were recorded for that. However the bonus game ended up being single player only.

Unused female fighter sounds

I found these all lumped next to each other in the sound test. I've no idea what purpose they serve, perhaps the game was going to have a new female character at one point, and her voice was partly recorded, but then the character got cut. They are located near some of Elena's voice clips though, so they might have had something to do with her.