General consensus is that it's an error handler.

It's kind of weird to bring the voice actors in for something like that.
Personally i think that's gonna be Mewtwo's guidance.

Considering that there is no trace of Mewtwo's data, it would be rather odd for them to record a voice over for a character they hadn't made yet.

Didn't people also find Ice Climbers in the Wii U version?

*Shrugs*

I don't think they did, Sakurai said that they were in the Wii U version but removed them when they couldn't get them working on the 3DS version.
I think there's still data on them in the 3DS version, with they're victory theme and chanting.

I'm free for the next half hour. Anyone wanna play Smash?

Let's rock.

Don't forget to change settings to stock instead of a 2 minute timer

Hope there's room for me! I had a rocky day at work and I need to Smash!