(It doesn’t do this because there aren’t established corpuses for the speech or writing patterns of nonnative speakers. They may never be needed if machine translation advances quickly enough, but as a tool for machine-aided self-instruction, this seems like a useful tech.) FWIW my son doesn’t know about TMNT cartoons yet: he just has a few treasured early reader storybooks picked up during bulk book sales at a local used bookstore. He refers to Splinter as “The Mouse Sunsaengnim” (which is close enough to what Splinter is: a mutant Rat Sensei).