Yesterday I tried Fluency Now Mac version.
Its target segment does not accept Japanese characters. Wow, what a splendid experience it is to be kicked out of this world!
How many Japanese are there? Is support worthwhile? Commercially, I mean. It's an island, isn't it?
Well, Japanese is mainly spoken in one country, but it has many native speakers (more than German or French, for example). And in the age of Unicode, it shouldn't be difficult to include support for it.