In Japanese, long vowels ā, ī, ū are written as ああ (aa), いい (ii), うう (uu). However, ē and ō, in most cases, written as えい (ei) and おう (ou), but in other cases as ええ (ee) and おお (oo).

For example:

  • 先生{せんせい} -> sensei
  • 姉さん{ねえさん} -> neesan

I used to believe that ei and ee are exactly the same, and should be pronounced as ē (ee) regardless of spellings.

But today I saw this answer by a native speaker: https://japanese.stackexchange.com/a/30039/30724

せ、ん、せ、い。 (or せ、ん、せ、え。)

They pronounced 先生 as either せ、ん、せ、い (se|n|se|i) or せ、ん、せ、え (se|n|se|e). This confuses me.

Should ei/ee, ou/oo be treated the same?


I can offer a little bit of insight on this. I teach English to young Japanese kids, and in a recent lesson, we were comparing the sounds of the names of different English letters and grouping them according to which names had similar sounds. For example, out of the letters A, N, Y, D, K, P, I, H, M, T, the task was to recognize that D, P, T all ended with "ee" sound.

Of course, for Japanese people, this is actually represented with the hiragana い ... as a result, many of my students thought that it was odd not to include A, K, I and Y in that group, because in the Japanese way of thinking about their sounds, they all end in い as well.

When I played the names of A, K, and H together, though, students realized that they were a better "grouping" because they all contained the "ay" sound, which in Japanese would be represented with the hiragana えい.

Likewise I and Y "go together because they both have the sounds あい.

I only use this example to point out that Japanese people are very attuned to the a, i, u, e, o sounds, and can easily distinguish between an elongated ええ (ee) and a blended えい (ei). In Naruto's answer from the other Stack Exchange link you found, where he said that Japanese people would "sound out" the word sensei like this

せ、ん、せ、い。 (or せ、ん、せ、え。)

I am not sure that they really would use the second version... the combination of えい is not meant to elongate the え... when I ask my fellow teachers to sound out words containing えい like sensei, they have always used せ、ん、せ、い, and not せ、ん、せ、え. The sound is noticeably different. "Relaxed" speech might produce a sound closer to せんせ without the い sound at the end, but that's not an acknowledgement of a deliberate elongation of え, that's just casual speech.

This reddit conversation follows a similar line of questioning, and might be useful:


おう on the other hand, is a different case. A う following a kana ending with an お sound elongates the お sound. う is a "weaker" sound than お, and becomes subsumed in it. When "saying it out slowly" however, Japanese people are likely to enunciate the う sound as "oo", mainly to clarify which kana to write down, not to imply that that is the proper pronunciation. This is because おお combinations also exist.

to sum up, えい sound combinations are NOT meant to elongate the え sound, and Japanese people are very aware of and can clearly hear the two separate sounds, while おう sound combinations ARE meant to elongate the お sound, and Japanese people recognize this elongation, and PROBABLY do not usually enunciate or clearly hear the う within the long sound.

The one exception for this is when the う sound following the お sound is not part of the same kanji the お sound is part of. As Eiríkr Útlendi mentioned in the comments, verbs ending in う with a preceding お sound will clearly pronounce the う, and this is because the う is the part of the word that identifies which type of verb it is, and which ends up being conjugated. Also, words consisting of multiple kanji, where one ends in お and the next starts with う, will follow this rule as well. Where there are both in a single kanji, however, the "elongated お" sound is the rule.

  • 1
    Wandering through the NHK Hatsuon Accent Dictionary, I see that they do differentiate おう vs. おー, indicating that sometimes the う is pronounced as う, and sometimes it extends the preceding お. The key determiner appears to be whether the う is part of the same morphological part of the word -- i.e., is it part of a single kanji, or is it part of the following kanji or verb ending. Examples: 追【お】う where the う is the inflecting ending is listed as オウ, while 凹凸【おうとつ】 where the う is part of the same 凹【おう】 kanji is listed as オートツ. This agrees with my own experience in conversing with native speakers. – Eiríkr Útlendi Dec 20 '18 at 18:22
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    the reddit link mentioned something about that as well... I thought it was a bit outside the concerns of the question, but I can put in a mention of that .... – ericfromabeno Dec 20 '18 at 18:35
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    "when I ask my fellow teachers to sound out words containing えい like sensei, they have always used せ、ん、せ、い, and not せ、ん、せ、え" This makes it sound like you're asking them to spell it... I think the only thing that matters is how it's said at normal speed. – Leebo Dec 20 '18 at 22:49
  • Very vivid examples. Thank you. So the "ei" in 先生 {sensei} and the "ee" in 姉さん ​{neesan} are different (/ei/ as in English "eight" vs long /e/) but the "ou" in 東京 {toukyou} and the "oo" in 十日 {tooka} are the same (long /o/), right? – Zhuoyun Wei Dec 21 '18 at 1:25
  • unless you speak 東京 {toukyou} and 十日 {tooka} slowly, yes. @Leebo, I didn't mean to imply that I was asking them to "spell" it... Only speak it clearly. There is a very clear difference between せ followed by い and せ followed by え, and I have not heard anyone elongate the え sound like that for that word or indeed other words with the え+い combination. – ericfromabeno Dec 21 '18 at 5:58

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