The game mixes both Japanese and English when it is set to English (and probably the other languages too). They use Japanese to fill in the untranslated text or text they couldn't translate (like the dialogue during the sex part). In a lot of places, I couldn't force it to use English. It was kinda random when Japanese was shown and most of it seemed programmatically forced when it was shown. The easiest solution was to just replace the Japanese with English as well. My reasoning being that if you were using my patch, it was because you wanted to play in English anyway, so it wouldn't matter. If you want to language hop between the two, you're outta luck. But as
warmgummybear said above, just remove the patch if you have it and you should be able to play in Japanese again.