Japanese Onomatopoeia: The Four Classes (giongo, gitaigo)

Japanese onomatopoeia is a single grammatical system, far broader than English words like "buzz" or "bang." It names real sounds and soundless states alike, from a dog's bark to the silent sparkle of stars.¹ For a learner, treating it as a system rather than a word list turns a wall of unfamiliar mimetic words into something readable.

This overview uses the four-class framework (giseigo, giongo, gitaigo, giyougo). With it, you can slot any mimetic word into a class and read its form for meaning.¹

Overview

Why onomatopoeia is a core system, not decoration

Japanese onomatopoeia (オノマトペ) is a cover term for two of its sub-classes: 擬音語 (giongo, sound words) and 擬態語 (gitaigo, state words). In NINJAL's words, オノマトペ is the general term for giongo and gitaigo.² It is a structured part of the vocabulary, not a marginal or playful add-on.

Counting only words that appear in dictionaries, Japanese has roughly 2,000 mimetic words.²³ Of those, the number in common everyday use is estimated at about 400 to 700.³

The scale that makes onomatopoeia unavoidable

A learner who skips mimetic words is skipping several hundred items of everyday vocabulary, not a handful of comic-book sound effects. The dictionary inventory sits near 2,000 words, with 400 to 700 in regular daily use.²³

The sound-symbolic vocabulary follows regular constraints rather than being assembled ad hoc. The first theoretical study of the system showed that these words form an intricate linguistic system.⁴ Mimetics are a standard part of the grammar. They function mainly as adverbs and, with する, as verbs.⁵⁶

Onomatopoeia is not slang. It appears in everyday speech, child-rearing, advertising, and manga and anime. Still, it leans expressive and conversational, so stiff formal writing often avoids it.⁷

The native terminology: gitaigo, giongo, and the rest

The 擬ぎ〜語ご naming pattern names sub-classes of オノマトペ. Here, 擬 means "imitate" and 語 means "word." NINJAL gives a five-way breakdown of the field.¹

Class	Reading	Domain
擬声語	giseigo	Voices of humans or animals1
擬音語	giongo	Sounds of nature or of objects1
擬態語	gitaigo	States of inanimate things1
擬容語	giyougo	States and manner of living things1
擬情語	gijougo	Human psychological states and sensations such as pain1

In the linguistics literature, these map onto three broad types: phonomimes (giongo and giseigo, imitating actual sound), phenomimes (gitaigo, depicting external states), and psychomimes (gijougo, depicting inner states). Sources do not always draw the divisions in the same way.⁶

This article uses the canonical four: giseigo, giongo, gitaigo, and giyougo. It treats 擬情語 (gijougo) as an optional fifth class. NINJAL lists all five; folding gijougo into gitaigo and giyougo for learners is a simplification, not a contradiction of the source.¹

Register and where you will meet them

Mimetics are standard vocabulary, not a slang register. The same word can read as casual or neutral depending on context.⁷ An N4 reader meeting these words for the first time should treat them as ordinary vocabulary to learn, not as optional flavour.

The hiragana-versus-katakana choice is itself a register signal: katakana skews loud, sharp, and emphatic, while hiragana skews soft and everyday.⁷

A conversational mimetic can read as too casual

Because mimetics lean expressive, a highly conversational one such as ぺらぺら ("fluently, chattily") can sound out of place in a formal report. The system is standard, but individual words still carry a register.⁷⁸

The four classes

The four classes sort along two cuts. First, ask whether there is sound. Then, within each group, ask whether the source is animate or inanimate.

擬声語 (giseigo): animate sounds

擬声語 (giseigo) represents the voices of living things: animal cries and human vocal sounds.¹ It is the sub-class closest to the English notion of onomatopoeia, since it imitates an actual audible voice.⁶

犬いぬは「ワンワン」と鳴なく。⁹
"A dog goes 'woof-woof.'"

猫ねこはにゃーにゃーと鳴なく。¹⁰
"A cat goes 'meow, meow.'"

Both sentences show the canonical giseigo frame: a quoted animal voice, then と, then 鳴く, a verb of crying or calling. The mimetic is in katakana here, matching the sharp-sound tendency.⁷

擬音語 (giongo): inanimate sounds

擬音語 (giongo) represents real sounds from nature and from objects.¹ It covers every non-voice acoustic event. The animate-versus-inanimate line is what separates it from giseigo, since both are phonomimes.¹⁶

A textbook giongo is ザーザー, the sound of heavy rain. NINJAL classes it among 自然界の音, the sounds of the natural world.¹ The example below uses キラキラ instead to show the linking と-adverb structure in a verified sentence. キラキラ is a borderline case, because the twinkling of stars is silent and so leans toward gitaigo.

紺碧こんぺきの夜空よぞらに星ほしがキラキラと瞬またたいていた。¹¹
"Stars were twinkling in the deep-blue night sky."

The placement of a silent sparkle in the giongo section is deliberate friction. The next two classes are where soundless words properly belong.

擬態語 (gitaigo): states and conditions

擬態語 (gitaigo) represents the states and conditions of inanimate things: soundless appearances and textures.¹ These are phenomimes, with no acoustic referent at all. That is what makes them hard for English speakers, whose "onomatopoeia" is sound-only.⁶

タイルはぴかぴか。¹²
"The tiles are shiny."

星ほしがキラキラしている。¹³
"The stars are shining."

納豆なっとうはねばねばしている。¹⁴
"Natto is sticky."

ぴかぴか and ねばねば are textbook gitaigo for texture and appearance. Here, ぴかぴか appears in the bare predicate slot (...はぴかぴか), while ねばねば appears in the ...している slot. Together, they illustrate two of the three ways a mimetic attaches to a sentence.¹

擬容語 (giyougo): manner of action

擬容語 (giyougo) represents the states and manner of living things: soundless manner of movement or behaviour.¹ The line between gitaigo and giyougo is the state of an inanimate thing (gitaigo) versus the manner of a living thing's action (giyougo). NINJAL draws exactly this animate-versus-inanimate cut within the soundless class.¹

トムはぐっすり寝ねている。¹⁵
"Tom is sound asleep."

タクシーはカタツムリと同おなじくらいのろのろ進すすんでいるように思おもえた。¹⁶
"The taxi seemed to crawl along as slowly as a snail."

ぐっすり (a manner of sleeping) and のろのろ (a manner of moving) both describe how a living thing does something. That is the diagnostic of giyougo. Each attaches as a bare adverb directly before the verb.¹

A note on the fifth class (擬情語 gijougo)

擬情語 (gijougo) represents human psychological states and sensations such as pain.¹ Some sources, NINJAL among them, list it as a separate fifth class for inner feeling. In the linguistics literature, these are the psychomimes.¹⁶

This article keeps the four-class frame and folds emotion words under gitaigo and giyougo for learners. That is a teaching simplification consistent with the literature, where phenomimes and psychomimes are often both labelled gitaigo.⁶

胸むねがドキドキするわ。¹⁷
"I have butterflies in my stomach."

ドキドキ shows why the fifth class is tempting: the pounding is a felt inner state, not an external sound or a visible motion. For a single-hub overview, treating it as expressive gitaigo is adequate. The boundary is real, but it is not load-bearing for an N4 learner.⁶

Form and patterns

Reduplication: the ABAB / repeated-mora shape

Full reduplication, the ＡＢＡＢ type seen in キラキラ and ドキドキ, is the single most common onomatopoeia shape. In NINJAL's analysis of 1,647 dictionary entries, the ＡＢＡＢ pattern accounts for 419 words, roughly 25% of the total.² The 1,647-entry count is drawn from the reference dictionary 『擬音語・擬態語辞典』.¹⁸

Repetition encodes ongoing, repeated, or continuous events. This is the iconic mapping where more form means more event.⁴ The doubled キラ in キラキラ and the doubled ドキ in ドキドキ both carry this sense of something happening again and again.

Suffix and modification patterns: っ, ー, り, ん

NINJAL identifies a set of recurring オノマトペ標識 (onomatopoeia markers, or form signals) and counts them in the same 1,647-entry sample.²

Pattern	Marker	Count in the 1,647-entry sample
ＡＢっ	sokuon 「っ」	212 words2
ＡＢり	trailing 「り」	141 words2
ＡっＢり	sokuon + り combined	103 words2
ＡＢん	trailing 「ん」	102 words2
long vowel	「ー」	example forms 「がーん」「ばちゃーん」2

Adding the sokuon っ (gemination) produces a more emphatic or emotive variant of the base word: ぴたり becomes ぴったり.⁴

ぱっと / ぱあっと¹⁹
"in a flash" versus "in a fuller, more drawn-out burst"

The sokuon っ sharpens, and the long vowel ー fills out. The pair above is a constructed minimal contrast, though the underlying principle that っ and ー alter intensity is sourced.²⁴

The marker counts describe one dictionary, not live speech

The pattern statistics above are corpus-grounded on a single 1,647-entry dictionary sample from NINJAL. They describe that lexicon's shape, not necessarily how often each pattern is spoken.²

How onomatopoeia attaches to a sentence

Mimetics function primarily as adverbs.⁵⁶ They attach in three main slots.

The first slot is mimetic plus quotative と, often before a verb of saying, sounding, or manner.

犬いぬは「ワンワン」と鳴なく。⁹
"A dog goes 'woof-woof.'"

The second slot is a bare adverb placed directly before the verb.

トムはぐっすり寝ねている。¹⁵
"Tom is sound asleep."

The third slot is mimetic plus する, which turns the word into a verb.

星ほしがキラキラしている。¹³
"The stars are shining."

The する-verbalization is a large topic in its own right. It covers intransitive eventive する with phenomimes and psychomimes, and is only previewed here.⁶

Hiragana vs katakana: the writing convention

The script choice is a tendency, not a rule. Hiragana is associated with soft, quiet, subtle words, and katakana with hard, loud, sharp sounds and emphasis. There are no definitive rules saying when to use one or the other.⁷

The verified examples in this article line up with that tendency. The sharp or emphatic words appear in katakana: ワンワン,⁹ にゃーにゃー,¹⁰ キラキラ,¹¹¹³ and ドキドキ.¹⁷ The soft or stative words appear in hiragana: ぴかぴか,¹² ねばねば,¹⁴ ぐっすり,¹⁵ のろのろ,¹⁶ and にこにこ.²⁰

Read the script as a loudness dial

When the same word could be written either way, katakana turns the volume up and hiragana turns it down. Treat the choice as a nuance signal rather than a spelling rule, since the tendency is not absolute.⁷

Nuance and usage contexts

One state, many words: intensity and shade

A single human or natural state can be divided among several mimetics that differ in class and shade. Class plus form encode the nuance. For smiling and laughing, にこにこ is a warm, friendly smile, while にやにや is a smug, leering, or suspicious grin.²⁰²¹

彼女かのじょはいつもにこにこしている。²⁰
"She is always smiling."

何なににやにやしてんの？気持きもち悪わるい。²¹
"What are you grinning like that for? It's creepy."

にこにこ and にやにや are both ＡＢＡＢ reduplications, and both verbalize with する. Yet they carry opposite affect. The shared English gloss "smile" hides the shade entirely.²⁰²¹

Why direct translation fails

Mimetics are ideophones: words whose meaning is bundled with affect, intensity, and manner. A one-word English gloss drops much of that meaning, so they resist one-to-one translation and are best learned by collocation and context.⁴⁶

This is why the same English "smile" maps onto にこにこ and にやにや with non-overlapping connotations. It is also why "slowly" loses のろのろ's tone of tedious sluggishness.¹⁶²⁰²¹ The practical move is to learn each mimetic with its typical collocate: ぐっすり with 寝る, ドキドキ with する, ねばねば with 納豆.¹⁴¹⁵¹⁷

Good to know

Decode the second kanji in each 擬〜語 name

Every class name shares 擬 ("imitate, mimic"). The second kanji states the domain. 声 ("voice") gives 擬声語, animate voices. 音 ("sound") gives 擬音語, object and nature sounds. 態 ("state, condition") gives 擬態語, the states of things. 容 ("form, appearance, manner") gives 擬容語, the manner of a living thing's action. 情 ("feeling") gives 擬情語, inner feelings, the optional fifth class. Because the second kanji literally names the domain, matching NINJAL's own definitions, the class names are self-explaining once decoded.¹

Classing キラキラ-type words as "real sound" giongo

A common error is filing キラキラ ("twinkling, sparkling") under 擬音語 because it feels onomatopoeic to an English ear. But キラキラ is soundless, a visual state, so it is 擬態語, even though it patterns with the same と and する frames as true sound words. The giongo-versus-gitaigo line is about whether there is an actual acoustic referent, not about how onomatopoeic the word feels.¹⁶

Dropping a casual mimetic like ぺらぺら into formal writing

Expressive mimetics lean conversational, so a word like ぺらぺら can read as too casual in a formal document.

トムは日本語にほんごがぺらぺらだ。⁸
"Tom is fluent in Japanese."

In a formal report, a plainer expression such as 流暢 (ryūchō, "fluent") fits better. Onomatopoeia is standard vocabulary, but it is not neutral-formal by default.⁷⁸

The class is a lens, not a hard label

Sources disagree on where to cut the field. Phonomimes may or may not be split into animate and inanimate. Phenomimes and psychomimes are often both called gitaigo; NINJAL lists five classes while many learner sources list three.¹⁶ Use the four-class frame as a sorting tool, and do not expect every word to have one correct box.

Reduplication means "it keeps happening"

The most common shape, ＡＢＡＢ at roughly 25% of the analyzed lexicon, maps repetition of form onto repetition or continuation of the event. ドキドキ is a heart beating again and again, and the doubled form makes that meaning visible.²⁴

See also

• Onomatopoeia + する: Verbalizing Mimetic Words
• Emotion Onomatopoeia: ドキドキ, ワクワク, イライラ
• Texture and Appearance Onomatopoeia: フワフワ, ザラザラ, ベタベタ
• Movement Onomatopoeia: ゆっくり, バタバタ, グルグル
• Onomatopoeia in Manga and Anime: ドカン, バーン, シーン
• Suru-Verbs (する-Verbs): How する Turns Nouns Into Verbs
• Japanese Quotation with と: How to Say What Someone Said or Thought
• When Native Japanese Words Are Written in Katakana: Emphasis, Onomatopoeia, Scientific Names, and Other Stylistic Uses
• How to Learn Japanese Vocabulary: A Strategy by Level
• How Japanese Slang Works: Semantic Shift, Clipping, and Net-Speak
• What Is Gairaigo? A Guide to Loanwords in Japanese

References

Footnotes

1. 国立国語研究所 (NINJAL). 「日本語を楽しもう！擬音語って？擬態語って？」, コラム「日本語１」(five-class breakdown). https://www2.ninjal.ac.jp/Onomatope/column/nihongo_1.html ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³ ↩¹⁴ ↩¹⁵ ↩¹⁶ ↩¹⁷ ↩¹⁸ ↩¹⁹ ↩²⁰ ↩²¹ ↩²² ↩²³

2. 国立国語研究所 (NINJAL). 「日本語を楽しもう！擬音語って？擬態語って？」, コラム「日本語２」(オノマトペ標識 / morphological-pattern statistics; total count ~2,000; sample of 1,647 entries). https://www2.ninjal.ac.jp/Onomatope/column/nihongo_2.html ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³

3. 国立国語研究所 (NINJAL). 「日本語を楽しもう！擬音語って？擬態語って？」, コラム「日本語３」(dictionary count of approximately 2,000+; everyday-use estimate of 400–700 words). https://www2.ninjal.ac.jp/Onomatope/column/nihongo_3.html ↩ ↩² ↩³

4. Hamano, Shoko. The Sound-Symbolic System of Japanese (Studies in Japanese Linguistics, vol. 10). CSLI Publications / Kurosio, Stanford & Tokyo, 1998. (Gemination/sokuon nuance; sound-symbolic system as structured.) ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

5. Shibatani, Masayoshi. The Languages of Japan (Cambridge Language Surveys). Cambridge University Press, 1990. (Mimetics as adverbs; quotative と and する.) ↩ ↩²

6. Akita, Kimi. A Grammar of Sound-Symbolic Words in Japanese: Theoretical Approaches to Iconic and Lexical Properties of Mimetics. Doctoral dissertation, Kobe University, 2009. (Phonomime / phenomime / psychomime grouping; mimetics as adverbs combining with と and する.) ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹ ↩¹² ↩¹³

7. Tofugu. "Japanese Onomatopoeia: The Definitive Guide." https://www.tofugu.com/japanese/japanese-onomatopoeia/ (limitation: learning-publisher source, used only for the hiragana/katakana writing-tendency framing.) ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸

8. Tatoeba sentence #199846. https://tatoeba.org/en/sentences/show/199846 ↩ ↩² ↩³

9. Tatoeba sentence #11605430. https://tatoeba.org/en/sentences/show/11605430 ↩ ↩² ↩³

10. Tatoeba sentence #121966. https://tatoeba.org/en/sentences/show/121966 ↩ ↩²

11. Tatoeba sentence #11286006. https://tatoeba.org/en/sentences/show/11286006 ↩ ↩²

12. Tatoeba sentence #10953687. https://tatoeba.org/en/sentences/show/10953687 ↩ ↩²

13. Tatoeba sentence #11110260. https://tatoeba.org/en/sentences/show/11110260 ↩ ↩² ↩³

14. Tatoeba sentence #121729. https://tatoeba.org/en/sentences/show/121729 ↩ ↩² ↩³

15. Tatoeba sentence #2128059. https://tatoeba.org/en/sentences/show/2128059 ↩ ↩² ↩³ ↩⁴

16. Tatoeba sentence #203713. https://tatoeba.org/en/sentences/show/203713 ↩ ↩² ↩³

17. Tatoeba sentence #180094. https://tatoeba.org/en/sentences/show/180094 ↩ ↩² ↩³

18. 天沼寧 (編). 『擬音語・擬態語辞典』. 東京堂出版, 1974. (Reference dictionary from which NINJAL's 1,647-entry analysis sample is drawn.) ↩

19. Constructed minimal example (no clean corpus sentence located). Not attributed to any source; included only to illustrate a form contrast. Vocabulary and gloss verified against ¹ and ⁴. ↩

20. Tatoeba sentence #93315. https://tatoeba.org/en/sentences/show/93315 ↩ ↩² ↩³ ↩⁴ ↩⁵

21. Tatoeba sentence #2684888. https://tatoeba.org/en/sentences/show/2684888 ↩ ↩² ↩³ ↩⁴