^We don't know if the coconuts were even offered Japanese lessons. Junjun and Linlin started learning Japanese (from actual tutors) immediately, but that doesn't mean it was the same back then, when H!P was still brand new. Not to mention they had a built-in translater (Ayaka) so it's possible that UFA didn't think lessons were necessary. But, don't be confused. The coconuts did introduce themselves in Japanese at concerts in the beginning and used the proper "yoroshiku onegaishimasu". And throughout their time there, you could hear improvements in Danielle's and Lehua's speech, as if they were picking up on key phrases that they learned from people around them, rather than being taught in a classroom.
Think about it. If they lived in Japan, sang Japanese songs, and went on Japanese talk shows, why on EARTH would they REFUSE to learn to Japanese??
And, um.... wtf does Nakazawa have to do with anything??
It seems like, when Coconuts first started, that Ayaka was super-shy, and that she kind of just got thrust into the role as leader, due to her being bi-lingual. Over her career in H!P, she really grew in self confidence, and charisma, not to mention talent as a singer and as a dancer. Should I mention that she got sexier, too? Well, Ayaka is in my top five idols. I enjoyed her surprise English lessons very much. I could watch those for hours on end. She took a lot of abuse from the other girls, just for trying to teach them English, and she always came across as extremely cheerful, and had a big smile. I wish Ayaka would make a comeback in the entertainment industry!