Lupita Nyong’o developed a vocal cord polyp due to the “super-positive voice” she used to play a robot in her upcoming film. The 41-year-old actress said she was forced to rest her voice for three months after she strained herself during her work on ‘The Wild Robot’ portraying cyborg Roz and its journey to finding “humanity”. She said on ‘Late Night with Seth Myers’: “(Roz) goes through this journey to finding, I guess, what we would call humanity, like empathy. “And so at the start of the movie, I chose to do this very, kind of like, super-positive voice. “And it was, like, just not in my voc…