Why Do We Read Wo (を) As “O (お)” in Japanese? :Konnichiwa, everyone! Today, we’re going to have a lesson centered on a phonetical point in the Japanese language. Why is the particle を (wo) pronounced the same as the hiragana character お (o)? We hope to give you a better understanding of this phenomenon in the following article. Here we go!

Anatanokoto wo(o) omoimasu.
I think of you.
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Why Do We Read Wo (を) As “O (お)” in Japanese?

So, it’s your first day of Japanese class, and your teacher gives you a printout of the Japanese syllabary. You go on down the list, repeating along with the teacher in correct Japanese…

  • あ  ➝  ah
  • い  ➝  ee
  • う  ➝  oo
  • え  ➝  eh
  • お  ➝  oh

Okay…seems straightforward enough for the first set of characters. The Japanese writing will take some getting used to, but you’re following along so far…

But then you arrive at the bottom of the page and see this を character. Next to it is the romanized pronunciation of “wo.

Oh…” the teacher says.

Whoa…” you repeat.

“No, no, no…” says the teacher, approaching your desk. “It’s ‘oh…’”

But you show her, right there on the page, there’s definitely a W there… 

Why does the お character have the same pronunciation as the を but is written “wo” in the romanization?

Ancient Japanese

When I was in high school, our teacher showed us The Canterbury Tales as it was written in its original Middle English in the late 1300s. We couldn’t understand a single word of it. This couldn’t be English! Even the letters were written differently.

The same goes for old Japanese. Most people in modern times would not be able to understand the Japanese of a thousand years ago because the language has evolved since then. 

Did you know that は・ひ・ふ・へ・ほ (hah, hee, foo, heh, hoh) used to be pronounced “pah, pee, poo, peh, poh” before the Nara period? And that during the Nara period (AD 710-794) it evolved to “fah, fee, foo, feh, foh?” Several other eras afterward would see further changes in Japanese pronunciation, and it would continue to evolve until the Shōwa period.

It is in these early times that characters ゐ (wee) and ゑ (weh) were also used. However, the pronunciation of ゐ and い were judged to be virtually indistinguishable by the Kamakura and Taishō periods and was thusly deemed obsolete and replaced entirely by い. The same happened with ゑ, which was replaced by え in 1946. 

To show you ways in which the pronunciations have evolved from olden times, here are some examples of words that once utilized the ゐ sound.

Old JapaneseRomajiModern JapaneseRomajiEnglish
用ゐる (もちゐる)mochiwiru用いる(もちいる)mochiruto utilize
行為(こふゐ)kofuwi行為(こうい)kouibehavior, action

Here are some examples of words that used ゑ.

Old JapaneseRomajiModern JapaneseRomajiEnglish

Modern Japanese 

After WWII, the Japanese government organized a language reform. They went through all of the old texts and developed a standardized pronunciation and hiragana/katakana spelling for all kanji. The problem they ran into was that Japanese particles such as は・へ・を had different pronunciations in the past than they did at present, and particles occur so frequently in the language that going through all the old writings and changing them to match the new pronunciations was too much work. 

They’d have to rewrite hundreds of year’s worth of books! 

Therefore, they left most of the particles as they were, and they now stand as exceptions to the rules of modern-day Japanese. This is why は is pronounced “wa” in 私は~ (watashi wa) and こんにちは (konnichiwa). The same goes for the particle へ as in 日本へ行きます (nihon e ikimasu, go to Japan). The correct pronunciation for へ is “heh,” but when used as a particle the modern-day pronunciation is “eh,” and going back to change all of the へ’s to え’s is too much work!

Which brings us to our particle of the day: を. Yes, just like は and へ, Japanese people of yore used to pronounce を with a W. Some dialects to this day still pronounce it like “whoa.” However, the standardized Japanese from the post-WWII Shōwa era says that it is pronounced just “oh.

In Summary

Like English, the Japanese language has evolved over the course of thousands of years. The particle を having the same pronunciation as the character お is an example of how the pronunciation has changed over time. In the distant past, the Japanese pronounced を like “whoa.” However, since then, the Japanese have rendered the W sound too subtle to have any significance. Therefore, the government changed the sound of を to just “oh” and made that the exception to the rule so that they didn’t have to go back and change all of the を’s to お’s in ancient texts.

What a pain, right?

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