Mr. Adventure wrote:
My edit came as you commented so I'm not sure if you saw it, have you been able to find any videos of Martha Miyake? My search has come up empty.
Not videos, but a couple of audio clips with still photos of her at a couple of different ages. Here's "Goody Goody"
from her album My Favorite Songs
. (Which is the first hit on her name on Google, so I'm surprised you missed it.) And on the homepage for the Martha Miyake Vocal House
, a music school she opened in Tokyo in 1974, there's a clip of her singing "What a Wonderful World" on her 45th Anniversary Edition
CD. It does sound like the same voice we hear in the movie.
I also found a reference on Google Books
confirming that "Yumi Shirakawa... was dubbed by Martha Miyake in both the Japanese and stateside versions." (The book also translates Ekitainingen
in the title as "Hydrogen Man" rather than "Liquid Man," but that seems to be an error. Japanese for hydrogen is suiso