I wonder if Helen Keller was ever brought up during Lilly's design process?

No, that would be more for Shizune when you think about it. Lily is only blind.

Wasn't Hellen Keller both blind AND mute because of a disease? I can't even imagine how communication works in that situation.

Edit: I mean blind and deaf. My bad.

She was blind and deaf. She was still able to speak. She was able to communicate with others by having others write what they are saying onto the palm of her hand. Not impossible to communicate, just really fucking hard.

She also learned how to speak by copying the vibrations of sounds in someone elses throat. She was really badass when you think about it.