Natural Japanese Series

Te Iru vs Teru, Te Oku vs Toku, Te Shimau vs Chau: What’s the Difference?

Japanese often sounds different in everyday conversation from the forms you learn in textbooks. In this guide, you will learn to recognize common shortened forms in natural spoken Japanese and understand what they mean in everyday conversation.

Written by Chiho Kamioka ·

Te oku vs toku in natural spoken Japanese: 〜ておく and the casual short form 〜とく

You may already know 何をしているの？ (nani o shite iru no?) from your textbook, but in everyday conversation you may hear 何してるの？ (nani shiteru no?).

At first, this may sound like a different expression, but it often comes from grammar you already know. In this guide, you will learn how common shortened forms are used in everyday conversation and what they mean.

Quick Guide: Are These Forms the Same?

Yes, within each pair, the basic meaning is generally the same. The shorter form is a common conversational version of the complete form. What changes most is how casual or conversational the expression sounds.

Full FormNatural Spoken FormBasic MeaningWhat’s the Difference?
〜ている
~te iru
 〜てる
~teru
 ongoing action or current state Same basic meaning. 〜てる is more casual and common in conversation.
〜ておく
~te oku
 〜とく
~toku
 doing something in advance or leaving something ready for later Same basic meaning. 〜とく is the more conversational form.
〜てしまう / 〜でしまう
~te shimau / ~de shimau
 〜ちゃう / 〜じゃう
~chau / ~jau
 completion, regret, or unintended action Same basic grammar and meaning. 〜ちゃう / 〜じゃう sound more conversational and casual.

The examples below show how these forms sound in real conversations and when you are likely to hear or use them.

What Is the Difference Between 〜ている (Te Iru) and 〜てる (Teru)?

〜ている: (te iru) is used for an ongoing action or a current state.

〜てる: (teru) is the casual shortened form.

Useful for

talking about what someone is doing, what is happening now, or someone’s current situation

Full form → Natural spoken form

今いま、何なにをしているの？ → 今いま、何なにしてるの？

ima, nani o shite iru no? → ima, nani shiteru no?

What are you doing now?

Conversation 1

A: 今いま、何なにしてる？

ima, nani shiteru?

What are you doing now?

B: 日本語にほんごの宿題しゅくだいをしてる。

nihongo no shukudai o shiteru.

I’m doing my Japanese homework.

Conversation 2

A: ごめん、あと10分ぷんくらいかかりそう。

gomen, ato juppun kurai kakarisou.

Sorry, I think I’ll be about 10 more minutes.

B: 大丈夫だいじょうぶ。駅前えきまえのスタバで待まってるよ。

daijoubu. ekimae no sutaba de matteru yo.

No problem. I’m waiting at the Starbucks in front of the station.

What Is the Difference Between 〜ておく (Te Oku) and 〜とく (Toku)?

〜ておく: (te oku) means doing something in advance or leaving something ready for later.

〜とく: (toku) is the casual shortened form.

Useful for

preparing something for later, making reservations, buying something in advance, or getting something ready

Full form → Natural spoken form

このケーキを冷蔵庫れいぞうこに入いれておくね。 → このケーキ、冷蔵庫れいぞうこに入いれとくね。

kono keeki o reizouko ni irete oku ne. → kono keeki, reizouko ni iretoku ne.

I’ll put this cake in the refrigerator for later.

Note: In casual conversation, particles such as を (o) are sometimes omitted when the meaning is clear. Here, このケーキを becomes このケーキ、.

Conversation 1

A: ビール、買かった？

biiru, katta?

Did you buy the beer?

B: まだ。帰かえりに買かっとくね。

mada. Kaeri ni kattoku ne.

Not yet. I’ll buy some on the way home.

Conversation 2

A: この店みせ、人気にんきらしいよ。

kono mise, ninki rashii yo.

I heard this restaurant is popular.

B: じゃあ、予約よやくしとくね。

jaa, yoyaku shitoku ne.

Then I’ll make a reservation in advance.

Note: When the te-form ends in 〜で, 〜でおく often becomes 〜どく in casual speech. For example, 読んでおく → 読んどく.

What Is the Difference Between 〜てしまう (Te Shimau) and 〜ちゃう / 〜じゃう (Chau / Jau)?

〜てしまう / 〜でしまう: (te shimau / de shimau) can express completion, regret, or an unintended action.

〜ちゃう / 〜じゃう: (chau / jau) are the casual shortened forms.

Useful for

talking about mistakes, something that happened unintentionally, or finishing something completely

Full form → Natural spoken form

忘わすれてしまった。 → 忘わすれちゃった。

wasurete shimatta. → wasurechatta.

I forgot.

飲のんでしまった。 → 飲のんじゃった。

nonde shimatta. → nonjatta.

I drank it.

Conversation 1: 〜ちゃう

A: ケーキ、まだある？

keeki, mada aru?

Is there any cake left?

B: ごめん。全部ぜんぶ食たべちゃった。

gomen. Zenbu tabechatta.

Sorry. I ate it all.

Conversation 2: 〜じゃう

A: 牛乳ぎゅうにゅう、まだある？

gyuunyuu, mada aru?

Is there any milk left?

B: ごめん。全部ぜんぶ飲のんじゃった。

gomen. Zenbu nonjatta.

Sorry. I drank it all.

Note: In the past tense, 〜ちゃう / 〜じゃう become 〜ちゃった / 〜じゃった.

When Should You Use the Full Form or the Contracted Form?

The difference is mainly one of style and situation. Shortened forms such as 〜てる, 〜とく, and 〜ちゃう / 〜じゃう are especially common in relaxed everyday conversation.

SituationWhich Form?
Conversation with friends or family Contracted forms are very common: 〜てる, 〜とく, 〜ちゃう / 〜じゃう
Casual messages or informal conversation Contracted forms sound natural
Formal or polite situations Use the non-contracted or polite forms, such as 〜ています, 〜ておきます, or 〜てしまいます

If you are still learning Japanese, you do not need to start using every contraction immediately. Being able to recognize them when you hear them is an important first step toward understanding natural spoken Japanese.

Mini Quiz: Can You Restore the Full Form?

Read each short conversation and identify the complete form behind the highlighted contraction.

A: 今いま、テレビ見みてる？

B: うん、見みてるよ。

Show Hint & Answer

Hint

A: ima, terebi miteru?

A: Are you watching TV now?

B: un, miteru yo.

B: Yeah, I am.

Answer

見みてる (miteru) → 見みている (mite iru)

A: 明日あしたのレストラン、予約よやくした？

B: まだ。今いま、予約よやくしとくね。

Show Hint & Answer

Hint

A: ashita no resutoran, yoyaku shita?

A: Did you make a reservation for tomorrow?

B: mada. Ima, yoyaku shitoku ne.

B: Not yet. I’ll make the reservation now.

Answer

予約よやくしとく (yoyaku shitoku) → 予約よやくしておく (yoyaku shite oku)

A: 傘かさは？

B: あ、電車でんしゃに忘わすれちゃった。

Show Hint & Answer

Hint

A: kasa wa?

A: What about your umbrella?

B: a, densha ni wasurechatta.

B: Oh, I left it on the train.

Answer

忘わすれちゃった (wasurechatta) → 忘わすれてしまった (wasurete shimatta)

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Japanese Contractions FAQ

What are contractions in Japanese?

Japanese contractions are shortened forms that are common in natural spoken Japanese. For example, 〜ている (te iru) often becomes 〜てる (teru), 〜ておく (te oku) often becomes 〜とく (toku), and 〜てしまう (te shimau) often becomes 〜ちゃう (chau).

Do Japanese contractions have the same meaning as the full forms?

In these examples, the basic meaning stays the same. The main difference is that shortened forms such as 〜てる, 〜とく, and 〜ちゃう / 〜じゃう sound more casual and are very common in everyday conversation. The full forms are generally more appropriate in formal or polite situations.

Is 〜てる the same as 〜ている?

Yes. In casual conversation, 〜てる (teru) is a common shortened form of 〜ている (te iru). The basic meaning stays the same, but 〜てる sounds more casual and conversational. For example, 何なにしてる？ (Nani shiteru?) is a common casual form of 何なにをしている？ (Nani o shite iru?).

Is 〜とく the same as 〜ておく?

Yes. 〜とく (toku) is a common conversational contraction of 〜ておく (te oku). Both can mean doing something in advance or leaving something ready for later. The main difference is that 〜とく is more casual and common in everyday conversation. For example, 予約よやくしとく (yoyaku shitoku) comes from 予約よやくしておく (yoyaku shite oku).

What is the difference between 〜てしまう, 〜ちゃう, and 〜じゃう?

〜ちゃう (chau) is the casual shortened form of 〜てしまう (te shimau), while 〜じゃう (jau) comes from 〜でしまう (de shimau). The basic grammar and meaning stay the same, but 〜ちゃう / 〜じゃう sound more casual and conversational. For example, 食たべてしまう (tabete shimau) becomes 食たべちゃう (tabechau), while 飲のんでしまう (nonde shimau) becomes 飲のんじゃう (nonjau).

Since 2006, Japonin has helped over 6,000 learners worldwide study Japanese online with support from our experienced Japanese language teachers.

Chiho Kamioka, Founder of Japonin

Written by Chiho Kamioka Founder of Japonin 

Learners may understand Japanese grammar when they see it in a textbook, but find it harder to recognize the same forms in everyday conversation. In this guide, I focused on helping learners connect common spoken forms such as 〜てる, 〜とく, and 〜ちゃう / 〜じゃう with the complete forms they may already know.

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