I have a few points regarding the Japanese translation:
Recently, lessons that I guess have no level assigned are displayed as “no knowledge.”
After some time, the display switched to Japanese as “まったくの初心者” (complete beginner).
However, “レベル未設定” (level unset) seems more appropriate.
The “History” category on the top page is translated as “履歴” in Japanese, which refers to a personal activity log.
The term “歴史” (history) would be more suitable in this context.
In the lesson summary, the phrase “500 Total Words | 100 Unique Words” is displayed. It would be more natural to translate it as “総単語数 500 | 異なり語数 100.”
If changing the order is technically difficult, “500 総単語数 | 100 異なり語数” would still make sense.
In the vocabulary list filter, the “Apply” button is translated as “適応”, but “適用” is the correct translation.
(This is a mistake even native speakers sometimes make.)
In the “Sort By” options, “A-Z” is translated as “アルファベット順” (alphabetical order), but “Z-A” has not been translated.
It’s not necessary to translate both.
I hope LingQ continues to improve and provide even better services.