On a CD that came with my text book I hear that desu is pronounced dess. Are there many other words in Japanese, where done of the sound from the kana spelling actually falls off, like in this example, at the end our at any other place?

If I pronounce desu instead of dess, will it sound wrong to native Japanese speakers?

Is there some rule to what vowels our other sounds (mora?) from the kanji to omit?



2 Answers 2


This is not a direct answer to your question but let me explain about difference between voicing/devoicing vowels and prolonging vowels.

There are several ways to pronounce です or the likes.

  1. des (1 syllable non-moraic 3 morae, /de/ is longer than /s/, sounds chopped foreign)
  2. des: (1 syllable 2 morae, /de/ and /s:/ are even, sounds eastern-dialect-ish)
  3. desu (2 syllables 2 morae, /de/ and /su/ are even, sounds western-dialect-ish)
  4. desu: (2 syllables 3 morae, /su:/ is longer than /de/, sounds feminine)

Japanese ears perceive no.1 as でぇす, no.2 and 3 as the same thing and normal pronunciation of です while no.4 as ですぅ, which is different from the rest and perhaps feminine.

However, English speakers perceive no.1 and no.2 as the same word "des" while no.3 and 4 as another same word "desu". If they fail to differentiate no.3 and 4, they may mix features unique to each of them.


In Japanese phonotactics, high vowels (for Japanese, these are i and u) have a certain property: they become unvoiced when surrounded by unvoiced sounds. Since the "u" in desu is surrounded on the left by "s" (voiceless) and on the right by nothing (nothing is also voiceless), the u is now voiceless. However, this rule is not universally followed; for example, it is common for women not to devoice vowels as much, as it is perceived as feminine. But in general, whenever these conditions are met, it is common for the vowel to become unvoiced.

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    I mean, there's no real use making a list... just look on Wikipedia for a listing of phonemes and allophones in Japanese, and pick out whichever ones are voiceless.
    – Kurausukun
    Commented Oct 11, 2016 at 20:08
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    If I occasionally pronounce desu instead of dess, will it sound wrong to native Japanese speakers? Commented Oct 11, 2016 at 20:37
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    @JirkaHanika: It's not exactly wrong, but it'll seem a bit odd (compare it to never using contractions in English). The extent of high vowel devoicing differs with register, but it's almost universal in 'desu' and 'arimasu'. (Incidentally, as a native English speaker, I find it easy to mispronounce 'desu yo' as 'desho(u)', which means something completely different. Voicing the final vowel in 'desu' would probably be a good idea in that case.)
    – anomaly
    Commented Oct 11, 2016 at 21:07
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    The best analogy I can come up with is that it would sound as "wrong" as if you actually said "I am going to go to the store." and fully pronounced the "ing" and the "to" instead of saying "I'm gonna go to the store"
    – Kevin
    Commented Oct 11, 2016 at 21:46
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    @JirkaHanika There are times when you should clearly pronounce the /u/, for example in polar questions ending in です (without か) where you need to pronounce the vowel and lengthen it very slightly to support the rising question intonation at the end of the sentence.
    – user1478
    Commented Oct 12, 2016 at 5:52

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