Why is ha は pronounced wa? Particles he へ as e, wo を as o?

One huge question people tend to have about Japanese is: why is the particle wa は pronounced wa わ despite the wa particle being written as ha は? And while we're at it, why is the particle e へ pronounced e え despite being written as he へ? And the particle wo を which sounds like o お anyway?! Why are these particles pronounced differently from what you'd expect?!

Well. In one word, the answer is: too much work.

Yep. Too much work.

Now, most people would just tell you: it doesn't really matter. Or: that's just how it is. Or: don't worry about it. Or even: Japanese natives don't care about this so why would you? But this post is different. This post will give you the real answers you're asking for. Answers which I don't really have by the way, because I'm not a historian specialized in Japanese language culture, so I'll just paraphrase an answer I've read on the internet for you.

Anyway.

History

Long, long, very long ago. Like 1000 years ago. Japanese pronunciation was different from what it is now.

And along the centuries that pronunciation changed. By a lot. Until it got the way it's now.

From P to W

For example, what is now ha-he-hi-ho-fu はへひほふ was once pronounced pa-pe-pi-po-pu. That is some quite different pronunciation right there. In order for the ancient pa to become the modern ha it had to go through a series of changes to become softer and softer.

So after some time, the ha ハ, or rather, pa パ changed into a softer fa ファ. The he ヘ, or pe ペ, changed into a softer fe フぇ. The hard p consonant changed into a softer f consonant.

The softening of the pronunciation continued with time. The soft f consonant got even softer and softer until fe フェ became we ウェ.

The fa ファ was still fa ファ. But it became wa ワ when it wasn't the first syllable of a word. That is, the modern ha は had two different pronunciations, fa and wa, and this could be root of later problems in Japanese language history.

Sample Words

To have an idea of how different things were, some sample pronunciations:

• hito 人
  fito フィト
  wito ウィト
• hana 花
  fana ファナ
• kawa 川
  kawa カハ

Now there are a couple of things you should notice.

First off, this F pronunciation of the H syllables that existed so long ago still exists today. The hu ふ syllable is really pronounced fu ふ in modern Japanese. So this F-ness wasn't something that just disappeared completely. It still exists. And above we can it where it came from exactly.

Second off, some words, like kawa 川, were once spelled differently: kawa かは (not kaha!) This is because back then fa は could also be read wa は. It was a mess. But we can see in this mess where the modern wa は particle and its pronunciation came from: at that time, the ha は kana could actually be pronounced wa ワ in normal words, not just in the particle.

From W to H

Next what happened was the shifting of this u ウ in some syllables sound to a hoarser i イ sound. For example, the he へ kana went from we ウェ to ie イェ. The hi ひ kana that was fi フィ then wi ウィ became just i イ. However the ha は kana stayed as a wa ワ pronunciation.

By the time Japan entered the Edo period, the pronunciation of he へ had gone from pe ペ, to fe フェ, to we ウェ, to finally just e エ. This was when the modern e へ particle and the e へ kana had the same pronunciation.

Now one might ask: why was e へ pronounced e え if there was already the e え kana?! Well, that's because those kana also went through multiple changes in pronunciation through history. The e え was once pronounced ie イェ. And also because people didn't really have much control over that.

By the time World War 2 happened, there were many kana that simple had the exact same pronunciation as other kana. It was a redundant mess. Everybody knew something had to be done, and then something was done.

The Japanese Language Reform

After World War 2, Japan went through a language reform that aimed to fix their mess of a language make things more standard and even across the country. One of the things that reform did was clean up the spelling of words and the pronunciation of the syllables.

It was in that reform that the e へ kana became officially pronounced he へ. If a word was written with he へ before the reform, the official spelling of the word changed to match the new pronunciation rules so that people wouldn't think the word was supposed to be pronounced with a he へ.

For example, mae 前 was spelled mae まへ, so its spelling changed to mae まえ, or else people would think it was pronounced mahe まへ. The word kawa 川 was written kawa かは, so it was changed to kawa かわ. Etc.

(by the way, as a Brazilian, I feel obliged to mention that Brazil did a spelling reform in such stupid way it managed to achieve the exact opposite of what Japan did. They removed the accent on ü and other words, making it so next generations won't be able to differentiate between gui and güi, which have different pronunciations. So in the future either lingüiça will be pronounced as enguiçar or enguiçar is pronounced like lingüiça. Either way one will be wrong. Honestly, why Brazil, why!?)

Problem With Particles

Anyway, Japan's language reform was proceeding smoothly until they ran into a little problem: the particles.

What is so special about the grammar particles in Japanese? Well, that would be the fact those particles are written with hiragana, not with kanji.

Think of it. Most Japanese words are written with kanji. The reform had changed the spelling of the hiragana, that is, which hiragana matched which sound. At very most you'd see the effect of this change in the furigana and in dictionaries, but nowhere else. This is because the reform didn't change how people pronounced the words, it just changed how to spell them with hiragana. Kanji was not affected by it at all!

(except, you know, by the fact the reform changed a lot about kanji too... but regarding the hiragana changes...)

Since the kanji was unaffected by this, most of the text was unaffected by this. But the particles were an exception. Because the particles were always written with hiragana.

Problem With Change

So Japan had all this text, books and books and books, where the wa ワ particle was written with the wa は kana, but this wa は kana was now pronounced ha ハ. These same books had the e エ particle written with e へ kana, but now that e へ kana was pronounced he ヘ.

They would have to change the text of all those books, not to mention the writing habits of all the Japanese people, to make them write the wa は particle as wa わ and then the e へ particle as e え. It was just too much trouble!

Do note that the wa particle is actually pronounced wa. That is, if the reform did occur, we would write it as kore wa neko desu これわ猫です, and nihon e 日本え, but we wouldn't pronounce it as kore ha neko desu and nihon he. People would pronounce the particles the same way they did before, all that would change was the spelling.

So Japan looked at all this work they had to do and gave up on it. After all, it just didn't make sense. It was unjustifiable to go through all that trouble just for two mere particles. So they left the two particles spelled "wrong" like that and made it so that was officially the "right" way to do it.

So there you have it. The reason why wa は and e へ are spelled like that is because those are the obsolete pronunciations of those kana. Every other word in Japanese has the modern pronunciation.

A fun fact: the sentence-ending wa わ particle historically comes from the wa は particle, but for some reason that one matches the modern spelling.

Problem With Irony

Ironically, when Japan made the wrong right, it consequently made the right wrong. Below we have one commonly misspelled word of the Japanese language:

• kon'nichi wa こんにちわ
  Good day.

Why is it wrong? Well, that's because, duh, you are supposed to write wa with the ha は kana, obviously! Shame on you for not knowing this. Shame on your family. Shame on your dog. Shame on your dog's ancestors. Everybody knows this! HOW U NOT KNOW DIZ?!??!!?

(reminder: a lot of people write kon'nichi wa wrong)

Seriously. The phonetic spelling is correct, but Japan officially made the wa は particle spelled wa は. So spelling kon'nichi wa 今日は with a wa わ is wrong because it'd be the right way to do it only if the reform hadn't given up on making the right way to do it the officially right way to do it. Since the official right way to do it is the wrong way to do it, doing it right is wrong.

Get it? No? Alright. Give up. Nobody cares about this. Maybe if people continue not caring about spelling the full reform will eventually take place because everybody will correctly "misspell" the particles and nobody will bother correcting them to the wrong right way.

Problem With Wo を

One last thing to explain, why wo を is pronounced o お.

Its history is likely the same as wa わ and e え, but there's a bit more to it.

During the Japanese reform, the kana wi ゐ and we ゑ were deemed obsolete and removed from the modern Japanese language.

This happened because wi ゐ was pronounced exactly like i い, we ゑ was pronounced exactly like e え. So they removed these kana to reduce redundancy in the language. (There isn't enough room in this language for two hiragana that are pronounced e! *bang bang*)

Just like wi was pronounced i and we was pronounced e, wo was also pronounced o. I think maybe it was going to be removed, too, leaving the W row of kana with just the wa わ syllable, but I wouldn't know that much. I just wanted to note that other W syllables had repeated pronunciations, and that those were indeed removed from the language, but wo was not.