Why is "Xy" pronounced as "[Ki Shi]{キ シ}" in [Xylitol]{キシリトール}?

I believe "Xy" can pronounced as "Zai", which is probably a valid sound in Japanese.

I would like to know its etymology too, if there is any.

  • 1
    It's obviously pronounced "Kishi" and not "Kishili". The "Li" part comes from "litol"…
    – Axioplase
    Commented Aug 28, 2012 at 4:21
  • Oh yeah, you're right @Axioplase, corrected
    – YOU
    Commented Aug 29, 2012 at 3:23

3 Answers 3


It comes from the Greek word xylon, which means wood. The Greek word xylon is pronounced "ksilon", so the Japanese transcription is faithful to the original Greek pronunciation, rather than the English corruption of the word.

See the answer to this question for the reason why "x" is pronounced "z" at the beginning of English words.

As for the origin of the word, the Greek word xylon means wood. The -itol suffix is added to denote that it is a sugar alcohol. It is produced from xylose, which was first isolated from wood (such as birch).

  • It might also have been borrowed from German, which preserves the /ks/ pronunciation for such words. Commented Feb 6, 2013 at 5:25
  • Actually (Ancient) Greek "x" is pronounced /x/, sort of like the "ch" in "Bach" in German.
    – ithisa
    Commented Feb 7, 2013 at 3:30
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    Hold on, user54609, no. Greek has two letters, Χ and Ξ. Their names are Chi and Xi in English. In Ancient Greek they were /kʰ/ and /ks/ respectively. In Modern Greek they are /x/ and /ks/ respectively. So the letter that looks like a Roman X is Chi. I think Xylitol in Greek is written something like Ξυλιτολ, but Modern Greek has a mandatory stress accent, so that's definitely wrong. ;p
    – user3167
    Commented Feb 9, 2013 at 13:21
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    Well, clearly, it's because this is chemically a sugar alcohol, and overconsumption can cause gas. Xylitol is less gas-producing than maltitol, for instance, so it causes lesser flatulence, more of a creaking than a farting. So the katakana rendering is fortuitously a native Japanese compound and nominalized verb, 軋り通る kishiritōru, literally meaning "creaking through". </oyaji_gyagu> Commented Jun 17, 2014 at 18:56
  • 1
    @EiríkrÚtlendi good job on that dad joke
    – psosuna
    Commented Feb 2, 2018 at 20:01

Xyl~ is the same as Xyl in Xylophone (coming from 'wood' in Greek). How it is pronounced varies between languages. You can see this by the explanation on the Japanese wiki article for Xylophone, which shows the different pronunciations in katakana:

Japanese: シロフォン

English: ザイロフォウン

German: クシュロフォーン

French: グジロフォヌ

Italian: クシロフォノ、シロフォノ

In German the IPA for Xylitol is ksyliˈtoːl, so キシリトール is likely to have come directly from German. Two groups, one French and one German, discovered Xylitol nearly simultaneously, so it makes sense for German to be the source language in this case.

  • 1
    It comes from Greek. Names of chemical compounds are always named after Greek words, primarily to avoid conflicts such as the one you mentioned. Commented Aug 27, 2012 at 15:27
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    @phoenixheart6 It may come from Greek etymologically, but it hasn't stopped English from saying it otherwise, so it's irrelevant. Greek is used to form words, but they are not directly borrowed from Greek so the original pronunciation is not retained.
    – alexandrec
    Commented Aug 27, 2012 at 23:40
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    @phoenixheart6: Just like English pronounces Greek words differently, Japanese could choose to pronounce Greek words differently. That the Japanese pronunciation resembles the Greek pronunciation doesn't mean it came from there... How many Japanese people do know Greek? I have to agree with nkjt, that the pronunciation most likely comes from German. The Japanese imported Western medicine from Germany and many words in the medicine, chemistry, etc. category are in fact based on German pronunciation, rather than English (or Greek).
    – Earthliŋ
    Commented Aug 28, 2012 at 3:22
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    [cont'd] That the German pronunciation represents the Greek pronunciation better than the English pronunciation is coincidental, but in this case ensures that the Japanese is still close to the Greek pronunciation.
    – Earthliŋ
    Commented Aug 28, 2012 at 3:25
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    The origin of the word is not a direct indication of its pronunciation -- scientific words are regularly created out of Latin and it's a dead language. In the case of xylitol, though the word may be Greek in composition, it is almost certainly not the case that the word actually came to Japanese (or any other language) from Greece per se.
    – alexandrec
    Commented Nov 6, 2012 at 14:53

I'd agree that it probably came from the German pronunciation, as they have taken a few loanwords from the German language, such as "doitsu-go" (I don't remember the romaji for it) which is "German" which comes from the German word "Deutsch" for the language. Or "arubaito" which comes from "albeit" or hobby or something. Its been about 6yrs since I studied Japanese, so apologies if I'm wrong or haven't used correct romaji.

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