Japanese Homophones: How Native Speakers Tell 科学かがく from 化学かがく Out Loud

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Once you know a few hundred kanji, a puzzle appears. A dictionary lists several different words read こうえん, and only the kanji tell them apart. So how does anyone follow a conversation, a lecture or the news, where there are no kanji to look at?

The answer is that Japanese speakers rarely have to choose. The sentence usually chooses for them. For the cases where it cannot, the language has a small set of repair tools, and you can use every one of them yourself.

This article is about different words that happen to sound alike. For one native word written with several kanji, such as 聞きく and 聴きく, see Same reading, different kanji.

Why so many Japanese words sound the same

Most of the trouble comes from Sino-Japanese words (kango), which are built from the Chinese readings (on'yomi) of kanji. Chinese, as it was spoken when these readings were borrowed, told syllables apart by tone, by a large set of vowels and by final consonants such as -p, -k and -ng. Japanese took the sounds without any of the tones and squeezed the vowels and endings into its own, much smaller sound system. Syllables that were distinct in Chinese fell together. In Mandarin today, 科学 is kēxué and 化学 is huàxué; in Japanese, both are かがく.

The old kana spelling, used until the spelling reform after the Second World War, still shows a few of the differences that have since disappeared. 公 was always こう; the other three were spelled differently and have merged into it:

Two-kanji words multiply the effect, because both halves can collide at once. That is how こうえん ends up as 公園こうえん (park), 講演こうえん (lecture), 公演こうえん (stage performance) and 後援こうえん (backing, sponsorship).

Context and partner words do most of the work

A homophone almost never arrives alone. It comes with a particle, a verb or another noun, and those partners usually fit only one meaning. Nobody plays in a lecture, and nobody listens to a park.

This is also the way to listen to the news. When you hear a homophone, hold off for one more word, because even a longer word may not settle it. こうえんかい can be a lecture event (講演会こうえんかい) or a politician’s supporters’ association (後援会こうえんかい), a fixture of election coverage. The words around it decide: 講演会こうえんかいに申もうし込こむ is signing up for a talk, and 議員ぎいんの後援会こうえんかい is a lawmaker’s support group. In the same way, きかいがあれば means “if I get the chance” (機会きかいがあれば).

Readings made up to avoid a clash

Some pairs turn up in exactly the same places, so context cannot help. A school can be しりつ in the sense of private (私立) or in the sense of run by the city (市立). A university course can be かがく as science (科学) or as chemistry (化学). For these, Japanese speakers use a second reading that exists only to avoid the clash. The デジタル大辞泉 dictionary lists each of the following and explains it as a way of keeping the word apart from its twin.

All four follow one recipe: swap the on'yomi of the troublesome kanji for its kun'yomi. A kun'yomi such as わたくし or ばける points to one character, while the on'yomi し or か is shared by a long list of kanji. These readings belong to speech. On paper the kanji already make the difference, so 化学 is still written 化学.

Pitch separates a few pairs

In standard Tokyo Japanese, some homophones differ in pitch. In the table, a line above a kana means it is said high, and a line turning down marks where the pitch drops. が is added because one pair only shows its difference on the particle.

Said on their own, 橋はし and 端はし sound the same; only the particle after them shows the drop. And pitch does not help with many pairs: 科学かがく and 化学かがく share one pattern, as do 公園こうえん and 講演こうえん, and 機械きかい and 機会きかい are usually said the same way too. That is exactly why a reading like ばけがく exists. Treat pitch as one more clue, keep in mind that other regions use different patterns, and check any word in OJAD, the University of Tokyo's online accent dictionary. For the basics, see our guide to pitch accent.

Describing a kanji in words

Sometimes the listener needs the character itself: on the phone, when someone gives their name, or when you are writing down an address. There is no standard way to name a kanji, the way a spelling alphabet names letters, so speakers describe the character with words the listener already knows. There are three standard ways, and you have already seen the first one at work in ばけがく.

The pattern 「AのB」 means “the B that appears in A”. A only has to show the shape, so it can even use a different reading: the 斉 in the surname 斉藤さいとう can be described as 一斉いっせいの斉, although 一斉 reads it せい. The one rule is to pick a reference word that has no twin of its own. Said aloud, かがくのか could be 科学の科 or 化学の化, so 教科書きょうかしょの科 and 化ばけるの化 are the safer choices.

Radical names are the vocabulary for the third method. These are the ones you will hear most often (more in our guide to radicals and their names):

• 氵さんずい · water
• 亻にんべん · person
• 木きへん · tree
• 扌てへん · hand
• 言ごんべん · words
• 糸いとへん · thread
• 艹くさかんむり · grass
• 宀うかんむり · roof
• ⺮たけかんむり · bamboo

When words run out, people trace the kanji in the air with a finger, or on the palm of their hand. Japanese psychologists call this 空書くうしょ, “air writing”. In a 1984 study, most Japanese students made these finger movements while working on kanji tasks, and students from countries that do not use kanji made none, which suggests the habit comes from years of writing kanji by hand.

Rephrasing: add a word or pick another one

The last tool is the simplest. Say it in a way that only fits one meaning.

What to do as a learner

1. Learn each word with its partners. Learn 講演こうえん as 講演こうえんを聞きく and 基調講演きちょうこうえん (keynote speech), not as a bare word with a translation. Then, when you hear こうえん, the next word decides it for you.
2. Ask when you cannot tell. どういう字じを書かきますか is a normal, polite question, and Japanese speakers ask each other the same thing about names.
3. Learn the kun'yomi of kanji you already know. Kun'yomi are how speakers point at one character: 化ばける in ばけがく, 会あう in 会あうの会. Our guide to on'yomi and kun'yomi explains which reading appears where.
4. Use the IME candidate list as a homophone drill. Type こうえん and press space, and your keyboard offers 公園, 講演, 公演 and more. Before you pick, say the partner word that goes with each one. If you have not set up Japanese input yet, see how to type Japanese.