Three Lexical Strata
Japanese vocabulary is often described in terms of three historical strata. 和語 (wago, "Japanese-language words") are the prehistoric native core — words that existed before writing, before Chinese influence, before history. 漢語 (kango, "Han-language words") are borrowings that arrived with Buddhism, Confucianism, and literacy from China, starting roughly in the 5th century CE. 外来語 (gairaigo, "words from outside") form a later borrowing layer, chiefly from Portuguese, Dutch, English and French, beginning with European contact from 1543, when a Portuguese ship first reached Japan.
Distribution by Domain
Each stratum dominates in different domains. National Institute for Japanese Language surveys find that in spoken Japanese wago exceed 70% of all running words — the ancient words for family, body, weather, emotion — while in newspaper prose it is kango that pass 70%, because Japan industrialized largely by coining kango compounds rather than borrowing Western originals. Words like 電話 (denwa, telephone), 経済 (keizai, economy), and 哲学 (tetsugaku, philosophy) were coined in Meiji Japan and later exported back to China and Korea — an example of technical vocabulary later moving from Japan into neighbouring languages.
The contrast among the three strata is visible in words for "beautiful":
- 美しい (utsukushii) — wago; ancient, warm, personal, used in poetry since the Man'yōshū
- 美麗 (birei) — kango; formal, objective, literary, used in prose and criticism
- ビューティフル (byūtifuru) — gairaigo; young, fashionable, often ironic or playful
The three choices differ in register and association. English has its own layered triples inherited from Germanic, French, and Latin — kingly, royal, regal; ask, question, interrogate. Japanese writing often makes the stratum visible through the choice of kanji, hiragana or katakana.
Writing and Lexical Strata
Japanese orthography often encodes stratum identity visually. Hiragana and kanji with kun readings signal wago. Kanji with on readings signal kango. Katakana signals gairaigo (and scientific names). These conventions can give a reader information about a word's likely history before its meaning is known. A sentence like 私はコーヒーを飲む ("I drink coffee") contains all three strata: 私 (wago), コーヒー (gairaigo from Dutch koffie), 飲む (wago).
When the Strata Collide
The three-stratum model breaks down at the edges. Many words are hybrids: 頭痛持ち (zutsū-mochi, "someone prone to headaches") welds the kango 頭痛 to the wago 持ち. チョコレート工場 mixes gairaigo (チョコレート, from English/Dutch/Portuguese) with kango (工場 kōjō, factory). Some words have been borrowed so long they feel native — tabako (tobacco, from Portuguese tabaco, brought in around 1600) feels as Japanese as sakura.
Mixed forms are conventionally labelled: 混種語 (konshugo), deliberate blends. テレビ局 (terebi-kyoku, TV station) fuses English gairaigo テレビ with kango 局. Such hybrids are common in modern Japanese and show that the three-way classification is permeable.
The three-stratum model is an analytical simplification, but it captures recurring differences in origin, register and spelling. A choice such as 美しい rather than ビューティフル can therefore convey both meaning and lexical register.