Long おう:What do お父さん and かき氷 have in common?

Hi, help me undersand:

I commonly mess up these two words and other similar because I don’t see the difference between the long おう (as in おとうさん、おとうと)、ice (氷 - こおり、かきごおり)。 I can’t really think of any more examples with long おお, I believe 大いに and such don’t count.

Does anyone know why does this change, instead of 氷 being: こうり? It seems like it would have to be also correct?

Thanks a lot, this is my first post I hope it makes sense to people.

I hope you are not messing up お父さん with かき氷 :wink:

Long and short vowels are important in Japanese, probably more important than in your native language. You have to learn it explicitly in the beginning, there is no specific reason why there is a short or long vowel. Just listen closely to the audio and after a while you will start hearing the difference. People will be really confused if you don’t follow it while speaking because many words already sound similar to begin with, without making mistakes.

The sound changes are also important, you can’t just choose what to do because you might land at a word with different meaning.

You can check at wikipedia for an overview:


It’s generally おう in on’yomi readings and おお in kun’yomi readings.

(I’m saying generally to be safe but I can’t think of any exceptions for now.)


It’s just spelling. I don’t think English speakers have any ground to stand on to criticize other languages’ spelling.


Plenty of native English speakers criticise their own language’s spelling! :rofl: What a hotchpotch!

Thank you, I also confuse these two and was hoping there might be a pattern.


Which reminds me of this video:

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I almost corrected your spelling to *hodgepodge and then I learned both are acceptable variants


What does this even mean?

Even ignoring 多い, you still have, 遠い、大阪、通り、十日, etc etc forever.

Etymologically, long お sounds written as ~おお used to be written (and I think pronounced) as ~おほ. These days there’s no difference in sound between ~おお and ~おう, though.


おほ and おを

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Thanks a lot for the replies. That’s what I was asking, why is 十日 in hiragana とおか and not とうか;

Was not intended as a way of criticising any language, just has me baffled and leads me to mistakes.


Ooh, do you have a source on that? Sounds seriously interesting.

Having some trouble finding any form of academic source, but this page touches on it: Modern kana usage - Wikipedia

The sound changes are pretty well attested but all you need to do is simply look at many J-J dictionaries and they will show the 旧仮名遣い, for 十日 you will see とを here on goo and とほり for 通り.

Huh. Can’t find おほ in particular in that first link you sent. Interesting, though.

Well, ~おう isn’t always pronounced like ~おお.

You’re right, I can’t seem to find it exactly mentioned. Basically the part that mentions it is: "By Late Middle Japanese, when these sounds were inside of a word, /ɸ/ became [w]. " And then these [w]s eventually fell off in the same way as ゐ and ゑ.

A little more is here and then a little more here

WO → O is one of the more recent sound changes which is why knowledge and usage of it still exists at least for を.

Yes, but 子牛 isn’t ~おう, it’s ~お+う.

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The reason why there’s お or う in long o- vowel. It comes from the history of the word and unfortunately there is no rules for that. You just have to remember which words take お and which う.

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