Update: I found it!
Attention #AppleNewton users … does anyone happen to have a copy of Enfour’s Japanese Newton Language Kit (NLK)?
It was made available to #MessagePad owners running the Japanese version of #NewtonOS.
Not sure if was a download of on CD. Even an exported copy of the packages would suffice.
Boosts welcome.
https://web.archive.org/web/19981206221059/http://www.enfour.co.jp/newton/news/nlk.html
Just arrived from Japan!
I hope the floppy still works.
@falken Turns out it may only be the large dictionary add-on package, not the entire NLK.
@falken Indeed, it was.