I'm not worried about whether you type the Japanese as long as you give me the English and I know it's supposed to be in Japanese. There will be some words--titles, in the main, although possibly also weapon names--that will be given in Japanese at all times despite the fact that I have English approximations.
If the roll is successful, you understood, even if some of the words were unfamiliar. Consider, if you like, the Lewis Carroll poem Jabberwocky, in which a substantial portion of the text is constructed of meaningless nonces, yet the listener follows the jist of the story nonetheless.
This will also cover the inherent problem that being immersed in a culture that speaks only this foreign language of which you understand only scraps, your character will undoubtedly learn much of the language considerably faster than you could, and thus his ability will improve gradually while yours will not, and we will have to rely on the rolls to tell us when you do and do not know what is being said or how to express yourself.
Also, at present I will allow certain "automatic" successes. I presume that you know how to say "thank you" and a few other "courtesy" words and phrases, and we'll allow them without a roll.
The hut is hand built of bamboo. He gestures for you to enter, saying something to the effect that he would be honored if you would accept the hospitality of food and shelter for the present. There is a woman probably near his age inside, and she looks up and asks perhaps a bit curtly who he has brought home this time. He responds, and you're pretty sure he said something about entertaining a ninja, which seems to satisfy her, or at least she turns and hurries to prepare something.
--M. J. Young