Casual Spoken Contractions | Japanese Grammar

There is a wall that almost every learner hits: you can read your textbook fine, you pass your grammar quizzes, and then you watch an anime or overhear two friends and understand almost nothing. The reason is rarely vocabulary. It is that spoken Japanese runs on a set of contractions that the written language quietly hides. 食べている becomes 食べてる, 行かなければ becomes 行かなきゃ, 〜てしまった becomes 〜ちゃった — and these reduced forms are not slang or sloppiness. They are the normal spoken register. Learn them and the wall comes down.

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These are phonological contractions of a casual register — completely standard in speech, texting, and casual writing, but avoided in formal writing, business email, and keigo. The rule of thumb: if you'd use plain form (〜だ／〜する) with the person, you'll use these contractions too. See Casual Plain Speech for the register they live in.

The core contractions at a glance

Full form	Contracted	Function
〜ている	〜てる	progressive / resultative state
〜ておく	〜とく	do in advance / for later
〜てしまう	〜ちゃう	completion / regret
〜でしまう	〜じゃう	completion / regret (after ん-sounds)
〜ては	〜ちゃ	in 〜ちゃだめ / 〜ちゃいけない
〜では	〜じゃ	じゃない, それじゃ, etc.
〜なければ	〜なきゃ	obligation ("gotta")
〜なくては	〜なくちゃ	obligation ("gotta")
という / と	って	quotative / topic marker
〜らない	〜んない	casual negative
これは / それは	こりゃ / そりゃ	demonstrative + は

〜ている → 〜てる (and 〜てた, 〜てて, 〜てない)

The single most common contraction in the language. The い of いる simply drops. This affects the whole progressive/resultative family: ている→てる, ていた→てた, ていて→てて, ていない→てない.

「今、何してるの？」「ネトフリで映画見てるだけ。」

ima, nani shiteru no? — netofuri de eiga miteru dake

'What are you doing right now?' 'Just watching a movie on Netflix.'

Full forms: 何をしているの / 見ている. Past tense contracts the same way:

ごめん、さっきからずっと外で待ってたんだよ。

gomen, sakki kara zutto soto de matteta n da yo

Sorry — I've been waiting outside this whole time.

待ってた = 待っていた (matte ita → matteta).

〜ておく → 〜とく / 〜でおく → 〜どく

The "do it in advance / leave it done" auxiliary おく collapses onto the て/で.

飲み物は私が買っとくから、席取っといてくれる？

nomimono wa watashi ga kattoku kara, seki tottoite kureru?

I'll grab the drinks, so can you save us seats?

買っとく = 買っておく; 取っといて = 取っておいて. (After the で-form it becomes どく: 読んでおく → 読んどく.)

〜てしまう → 〜ちゃう / 〜でしまう → 〜じゃう

しまう marks completion — often with a nuance of "oops" or "regrettably, it's all done." The contraction splits by sound: て-verbs take ちゃう, and で-verbs (the ん-ending group: 〜ぬ/ぶ/む/ぐ) take じゃう.

やばい、ぼーっとしてたら電車行っちゃった。

yabai, bōtto shitetara densha itchatta

Oh no — I spaced out and the train left.

行っちゃった = 行ってしまった. And the じゃう variant:

えっ、私の分のケーキ、もう食べちゃったの？

e', watashi no bun no kēki, mō tabechatta no?

Wait — you already ate my slice of cake?

買ったばかりのビール、一晩で全部飲んじゃった。

katta bakari no bīru, hitoban de zenbu nonjatta

I drank all the beer I'd just bought in a single night.

飲んじゃった = 飲んでしまった (で-form → じゃう).

〜ては → 〜ちゃ / 〜では → 〜じゃ

The topic-marked て/で contracts to ちゃ/じゃ. You meet ちゃ most in the prohibition 〜てはだめ／いけない → 〜ちゃだめ／いけない, and じゃ everywhere が negation and connectives.

あ、ここで写真撮っちゃだめだよ。看板に書いてある。

a, koko de shashin totcha dame da yo. kanban ni kaite aru

Oh, you can't take photos here — it says so on the sign.

撮っちゃだめ = 撮ってはだめ. The では → じゃ contraction is just as constant:

これ、私のじゃないよ。それじゃ、誰のだろう？

kore, watashi no ja nai yo. sore ja, dare no darō?

This isn't mine. So then, whose is it?

じゃない = ではない; それじゃ = それでは.

〜なければ → 〜なきゃ / 〜なくては → 〜なくちゃ

The two ways to say "have to" both contract. The 〜ければ／〜くては tail drops, and the leftover なきゃ／なくちゃ can even stand alone (the ならない／いけない being understood).

うわ、もうこんな時間だ。そろそろ行かなきゃ。

uwa, mō konna jikan da. sorosoro ikanakya

Whoa, it's already this late. I'd better get going.

行かなきゃ = 行かなければ(ならない).

今日中にこの薬、飲まなくちゃいけないんだった。

kyō-jū ni kono kusuri, nomanakucha ikenai n datta

Right — I have to take this medicine by the end of today.

飲まなくちゃ = 飲まなくては.

という / と → って

The quotative and topic-introducing って is one of the most useful reductions there is. It stands in for という (introducing/naming a topic) and for the quotative と (reporting speech or hearsay).

田中さんって、もう会社辞めたんだって。

Tanaka-san tte, mō kaisha yameta n datte

Tanaka — apparently she already quit the company.

Here って appears twice: 田中さんって = 田中さんというのは／は (topic), and 辞めたんだって = 辞めたんだと（聞いた）(hearsay "I hear that"). Reported speech leans on it constantly:

天気予報で、明日は一日中雨だって言ってたよ。

tenki yohō de, ashita wa ichinichi-jū ame datte itteta yo

The forecast said it's going to rain all day tomorrow.

〜らない → 〜んない

In casual speech the ら of a negative often nasalizes to ん before the ない. It sounds heavier and more colloquial than the full form.

ごめん、何言ってるのか全然わかんない。

gomen, nani itteru no ka zenzen wakannai

Sorry, I have absolutely no idea what you're saying.

わかんない = わからない. Same with any 〜らない:

正直、その映画めっちゃつまんなかった。

shōjiki, sono eiga meccha tsumannakatta

Honestly, that movie was super boring.

つまんなかった = つまらなかった.

これは → こりゃ, それは → そりゃ, and dropped particles

Demonstrative + は contracts to こりゃ／そりゃ／ありゃ, and in the same casual register the particles を, は, and が are frequently dropped altogether (covered on Dropped Particles).

そりゃそうだよ、こんな時間に電話したら迷惑に決まってる。

sorya sō da yo, konna jikan ni denwa shitara meiwaku ni kimatteru

Well, of course — calling at this hour is obviously a nuisance.

そりゃ = それは; note 決まってる (=ている) riding along too.

Bonus: 〜です → 〜っす

A very common (informal) — and mildly rough/masculine — reduction, heard from younger men, juniors to seniors, and in service and sports settings. です shrinks to っす, giving a tone that is casual but still trying to be a bit polite.

お疲れっす！明日の練習、朝九時からで大丈夫っす。

otsukare ssu! ashita no renshū, asa kuji kara de daijōbu ssu

Good work today! Tomorrow's practice is fine starting at 9 a.m.

お疲れっす = お疲れさまです; 大丈夫っす = 大丈夫です.

Why this matters more than it looks

Notice what all of these share: they compress two or three morae into fewer, and they cluster at exactly the grammatical joints — auxiliaries, negatives, quotatives — that carry a sentence's meaning. That is why textbook-only study leaves you stranded in real conversation and unable to follow anime or variety shows: the words you were taught are still there, but they've been worn smooth at the seams, and if your ear only knows the full forms it can't find them. Training yourself to hear 行っちゃった as 行ってしまった is not optional polish — for listening, the contracted forms are the primary form. See also the intonation of questions and final particles, which pile on top of these contractions in real speech.

Common mistakes

Mistake 1: Not recognizing the contraction while listening. You hear 待ってたんだよ and freeze because you're searching for 待っていた. The fix is to over-learn the pairs until the mapping is automatic.

✅ 待ってた = 待っていた

matteta = matte ita

Train your ear: the contracted form is the one you'll actually hear.

Mistake 2: Using these in formal writing or keigo. Casual contractions in a business email or a polite request sound jarringly out of place. Restore the full, polite forms.

❌ 資料、送っときますね。（取引先へのメール）

shiryō, okuttokimasu ne — in a client email

Incorrect — 送っとく is too casual for a client.

✅ 資料をお送りしておきます。

shiryō o ookuri shite okimasu

I'll send the materials over (humble/polite).

Mistake 3: Choosing ちゃう vs じゃう wrong. ちゃう goes with て-verbs; じゃう goes with the で-verbs (the ん-ending 〜ぬ/ぶ/む/ぐ group). 飲む is a で-verb, so it's 飲んじゃう, never 飲みちゃう.

❌ 飲みちゃった

nomichatta

Incorrect — 飲む is a で-verb, so it takes じゃう.

✅ 飲んじゃった

nonjatta

I (regrettably) drank it all up.

Mistake 4: Treating them as "wrong" or slang. They are neither — they are the standard casual register. Refusing to use any contraction with friends sounds stiff and textbook-ish, the mirror image of using them with your boss.

Mistake 5: Over-politening っす into formal speech. っす is casual; in genuinely formal situations use full です／ます. It signals "friendly junior," not "polished professional."

Key takeaways

Spoken Japanese is full of standard casual contractions — てる, とく, ちゃう/じゃう, ちゃ/じゃ, なきゃ/なくちゃ, って, んない, こりゃ/そりゃ, っす — that written and formal Japanese hides.
They cluster at grammatical joints (auxiliaries, negatives, quotatives), which is why not knowing them wrecks listening comprehension.
They belong to the plain/casual register: standard in speech and texting, out of place in formal writing and keigo.
ちゃう pairs with て-verbs, じゃう with で-verbs — match the contraction to the verb's て/で form.

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