You're right. The Backlit Portable INIT wasn't localized in Japanese (current versions of system software, 6.0.7 and 6.0.7.1). So to use KanjiTalk on the Backlit Portable, you'll need to use U.S. Portable INIT to control the screen brightness.
Article Change History:
13 Jul 1994 - Reviewed for technical accuracy, revised formatting,
clarified title.
25 Sep 1992 - Reviewed for technical accuracy.