turning Japanese

Yoshi speaks to Mabel in Japanese. I don't understand much Japanese. It appears that Mabel does. I generally have a facility with languages, but Japanese is more difficult for me than French and German, both of which I understand and read reasonably well with the help of a dictionary. Of course, if I were a more diligent student, my Japanese would be better. Yoshi gets frustrated with me; because his English is so good, I take it for granted and sometimes forget that he cannot express himself fully. But Mabel understands him when he speaks to her in Japanese. Maybe she can convey his thoughts to me.