I'm not fluent enough to read in japanese, but I noticed something funny... I mostly read books in english, but sometime find some interesting books in french too
(I set my main language to french on the device, as I'm French). Lately, I encountered a word in a french book that I wanted to look at. I selected it and it was the english-english dictionnary that popped up, no way to have access to the french-french dictionnary
An other thing : no proper name show up in the dictionnary (that can be useful to place a town or an historical character).