Chapter 13: The Very Secret Diary

Simplified Chinese (Mandarin: China)
绝密日记 Juémì rìjì	绝密 juémì = 'top-secret'. 日记 rìjì = 'diary'.	The Top-Secret Diary
Traditional Chinese (Mandarin: Taiwan)
絕密日記 Juémì rìjì	絕密 jué-mì = 'top-secret'. 日記 rìjì = 'diary'.	The Top-Secret Diary
Japanese
重大秘密の日記 Jūdai-himitsu no nikki	重大 jūdai = 'major/important' 秘密 himitsu = 'secret'. の no = connecting particle 日記 nikki = 'diary'	The Diary of Important Secrets
Korean
비밀 일기 Bimil ilgi	비밀 (秘密) bimil = 'secret'. 일기 (日記) ilgi = 'diary'	The Secret Diary
Vietnamese (Chinese characters show etymology)
Cuốn nhật ký cực kỳ bí mật	cuốn (卷) = counter for books. nhật ký (日記) = 'diary'. cực kỳ (極其) = 'extremely, utterly, very'. bí mật (秘密) = 'secret'.	The Extremely Secret Diary
Mongolian (previous)
Нууц өдрийн тэмдэглэл Nuuts ödriin temdeglel	нууц nuuts = 'secret'. өдрийн тэмдэглэл ödriin temdeglel = 'journal, diary'.	The Secret Diary
Mongolian (new)
Маш нууц өдрийн тэмдэглэл Mash nuuts ödriin temdeglel	маш mash = 'very'. нууц nuuts = 'secret'. өдрийн тэмдэглэл ödriin temdeglel = 'journal, diary'.	The Very Secret Diary

The 'very secret diary' is Tom Riddle's diary that Harry found in Myrtle's toilet.

How is 'very secret' translated?

To express the concept of 'very secret', the two Chinese versions use the snappy compound 絕密 / 绝密 juémì ('absolute-secret').
Japanese, Korean and Vietnamese all use the same word for 'secret' (秘密 himitsu in Japanese, 비밀 bimil in Korean, bí mật in Vietnamese), a term with Chinese roots.
- In the Japanese translation, this is qualified as 重大 jūdai, which means 'important', 'major', or 'grave'.
- Vietnamese uses cực kỳ meaning 'extremely, utterly'. Note: In the page headers in the initial instalments, the Vietnamese translation uses the title Cuốn nhật ký bí ẩn, where bí ẩn means 'secret, covered, veiled'. Etymologically, bí ẩn is 秘隱 in Chinese characters.
- The Korean translation does not translate the word 'very'.
Like the Korean, the previous Mongolian translation uses нууц nuuts 'secret' without qualification. Нууц nuuts is related to the verb нуух nuukh 'to hide'. The new Mongolian translation adds маш mash 'very, highly' to translate 'very'.

The five CJKV translations use the same etymologically related word for 'diary':
- 日記 (Trad.) / 日记 (Simpl.) rìjì in Chinese.
- 日記 nikki in Japanese.
- 일기 ilgi in Korean.
- nhật ký in Vietnamese.
This combines 日 'sun, day' and 記 / 记 meaning 'a mark, a sign' as a noun, and 'remember, note' as a verb. The meaning is 'daily notes' or 'daily record'.
Mongolian uses the combination өдрийн тэмдэглэл ödriin temdeglel 'daily record' for a journal or diary. Тэмдэглэл temdeglel 'record, note' is from the verb тэмдэглэх temdeglekh 'note down, stamp, mark, note', derived from the noun тэмдэг temdeg meaning 'sign, symbol, mark, badge'.

(Korean appears thanks to "Hiro".)

(Detailed notes on the chapter can be found at Harry Potter Lexicon)