Also, in that particular example, I don't think they made the guitar emit the voice-sounding sounds, but rather generated it electronically. It's not even obvio

Also, in that particular example, I don't think they made the guitar emit the voice-sounding sounds, but rather generated it electronically. It's not even obvious that the voice comes from guitar sounds... it actually sounds like a plain voice with effects. As opposed to, say, Mark Rober's talking piano.