What does an apostrophe (') mean in English translations of Japanese words? For example, an online grammar site says, "When you contract te oku to t'oku…."

Although just a beginning-level student, I have come across this numerous times, both online and in English-language books. I do not know how to determine what kana have been replaced by the apostrophe. Or, perhaps it represents a brief pause in pronunciation, like that made with doubled consonant sounds?

  • 1
    I believe you answered your own question... It's marking a contraction. In English the apostrophe is used the same way e.g. cannot -> can't, do not -> don't
    – psosuna
    Commented Dec 31, 2017 at 17:04
  • Is this a common notation for transliterating Japanese? I only know of the apostrophe being used for disambiguation as in kan'i vs. kani.
    – Earthliŋ
    Commented Dec 31, 2017 at 17:08
  • But when does one decide that a Japanese word becomes contracted versus the words that do not? Lists of Japanese punctuation marks do not seem to include the apostrophe, so I am guessing that this mark appears only in translations. When I see an anglicized word with an apostrophe, I do not know how to interpret what is missing .
    – NattoYum
    Commented Dec 31, 2017 at 17:13
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    t'oku isn't a translation, nor is it anglicized. It's still Japanese, but it's written in Latin letters. It's just another way of writing とく. Don't confuse the Japanese language with the Japanese writing system; they're two different things.
    – user1478
    Commented Dec 31, 2017 at 17:45
  • Thank you, snailplane. So if I see English letters with an apostrophe among them, do I just ignore the apostrophe and change the romaji to the kana that I would use irrespective of the apostrophe?
    – NattoYum
    Commented Dec 31, 2017 at 17:49

4 Answers 4


The typical use of an apostrophe in Romanized Japanese is to show that the original Japanese is N (ん) and not one of the na-ni-nu-ne-no (なにぬねの) series of letters. Sometimes these can be confused when Romanizing the original Japanese.


The case where the apostrophe is used to avoid ambiguity is already mentioned in the comments of the question and NattoYum's own answer, but this is not the case in "t'oku".

As noted by psosuna and others, it means contraction, and the change from "te oku" to "t'oku" is 音便. I don't think that is standard in transliterated Japanese however, and I have seen many grammar sites that introduce this grammar without using the apostrophe.


The original, historical purpose of the apostrophe is to show that something is left out:

  • le homme → l'homme  (an obligatory contraction in French)
  • I am → I'm  (an optional contraction in English)

In other words, it marks a contraction.

It's used that way in most modern Latin orthographies and is not specific to English. It is not commonly used that way in Latin transcriptions ("romanization") of Japanese, but if an author is specifically discussing contractions in a linguistic context it should be clear what it means:

  • -te oku-t'oku  (an optional contraction in Japanese)

The /e/ sound is elided and the apostrophe (in this case) indicates that contraction. The transcription -te oku represents the same sounds as ておく, and -t'oku represents the same sounds as とく. The only difference is that the Latin transcriptions use a dash to show an affix boundary and an apostrophe to mark elision.

No kana has been replaced with an apostrophe, as you write; the kana て represents a sequence of two phonemes, only one of which has been elided.

Although contractions are not marked in most transcriptions of Japanese, this convention has been used by linguists such as Samuel Martin, and it should be readily understandable in the proper context – if someone writes "contract te oku to t'oku", the only sound that could have possibly been left out is /e/.

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    Another interesting convention can be found in Anti-Homophony Blocking and its Productivity in Transparadigmatic Relations (Ichimura 2006), where the letters representing the affected sounds are simply bolded, e.g. boku -wa → bokaa, boka
    – user1478
    Commented Feb 1, 2018 at 4:55

Googling with the word "transcription," I was able to compile the following answer:

The apostrophe is used before the romaji letters a, i, u, e, o, y when they follow n/ん in order to distinguish, for example, kani from kan'i. The apostrophe makes it clear that ren'yōkei means …んよ… and not …にょ… as in renyōkei.

The Japanese government’s guidelines for romanization suggest inserting apostrophes in these situations:


The apostrophe is also part of the romanization system used by the U.S. Library of Congress, a system based on the revised Hepburn system (first laid out in Kenkyusha's New Japanese-English Dictionary, 3rd ed.):

Transcribe the apostrophe ( ' ) between syllables when the first syllable ends with the letter n and the following syllable begins with the letter a, i, u, e, o, or y and when it is necessary to separate romanization.


Nagai Ken'ichi/長井憲一

From Wikipedia:

In the revised Hepburn system the apostrophe is used to mark “the separation of easily confused phonemes (usually, syllabic n/ん from a following naked vowel or semivowel). For example, the name じゅんいちろう, is written with the kana characters ju-n-i-chi-ro-u, and romanized as Jun'ichirō in Revised Hepburn. Without the apostrophe, it would not be possible to distinguish this correct reading from the incorrect ju-ni-chi-ro-u. This system is widely used in Japan and among foreign students and academics.”

  • Paragraphs dude...
    – istrasci
    Commented Jan 30, 2018 at 21:53

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