てる・
How common spoken contractions work
Treat each contraction as a shorter pronunciation of a full grammar pattern. Expand it first, then interpret the full pattern: the shortening changes the conversational tone, but it does not invent a new tense or meaning. What follows the shortened sound is often the key to identifying it.
Expand first, then interpret
When you hear a short form, identify the full construction that could have produced it.
An ongoing action, resulting state, or habit
てる
The full form is ている or でいる. Context still decides whether it describes something in progress, a present state, or a habit.
Past, negative, and polite forms can also contract, as in てた, てない, and てます.
Preparation or leaving something in a useful state
とく・どく
The full form is ておく or でおく. It can express advance preparation, a temporary choice, or maintaining a state.
The ending can change normally, producing forms such as といた, とかない, and とこう.
Completion or an unwanted result
ちゃう・じゃう
The full form is てしまう or でしまう. It may simply emphasize complete action; regret or accident comes from context.
Do not assume that every use expresses a mistake.
A conversational prohibition
ちゃいけない・じゃいけない
The full form is てはいけない or ではいけない: the action is not allowed.
The visible いけない distinguishes this from the completion contraction.
A conversational obligation
なくちゃ・なきゃ
These shorten patterns beginning with なくては or なければ and mean that an action has to be done.
The rest of the obligation expression is often omitted when the consequence of not acting is obvious.
A conversational even-if condition
たって・だって
These correspond to ても・でも and say that the following result remains true even if the first condition holds.
だって has several unrelated uses, so identify it from its place in the sentence and the even-if meaning.
The same verb, two different full forms
Someone mentions the materials for tomorrow.
今、明日の資料を読んでる。
I'm reading tomorrow's materials now.
AnalyzeExpand 読んでる to 読んでいる: the reading is in progress.
明日の資料を先に読んどく。
I'll read tomorrow's materials in advance.
AnalyzeExpand 読んどく to 読んでおく: the reading is preparation for later.
Takeaway: The similar sounds do not make these interchangeable. Ask whether the full construction is ている or ておく.
Listen beyond the shortened sound
ちゃう by itself points to completion or a possibly unwanted result. When いけない follows, the source is instead the prohibition pattern. The continuation, not just the opening sound, decides the meaning.
Obligation can stop early
These forms begin from the verb's negative form. A self-reminder often leaves the final negative evaluation understood, while a fuller sentence states it.
Recognizing the even-if contraction
In this use, the first part names a condition that might be expected to affect the outcome, and the next part says the outcome will still hold. For verbs, the contracted form resembles the plain past followed by another って. A standalone or sentence-initial だって may have a completely different job, so spelling alone is not enough.
雨が降ったって、予定は変えないよ。
Even if it rains, I won't change the plan.
AnalyzeThe neutral full form is 降っても. The unchanged plan makes the even-if relationship clear.
Shortened beginnings, surviving endings
The recurring sound changes are ている to てる, ておく to とく, てしまう to ちゃう, and ては to ちゃ. Forms built with で produce voiced versions such as どく and じゃう. Whatever ending survives can still show past, negative, or polite form. That is why learning only one frozen short form is not enough.
More examples across the family
会議室の窓、開けといて。
Leave the meeting-room window open.
AnalyzeThis expands to 開けておいて and asks the listener to maintain the open state.
鍵を家に忘れちゃった。
I accidentally left my key at home.
AnalyzeThis expands to 忘れてしまった; the situation supplies the unwanted-result reading.
廊下を走っちゃいけません。
You mustn't run in the hallway.
AnalyzeThis expands to 走ってはいけません. The final ending is polite, but the contraction remains conversational.
この書類、今日出さなくちゃ。
I have to submit this document today.
AnalyzeStart from 出さない. The full obligation can be understood as 出さなくてはいけない.
何度説明したって、彼は考えを変えない。
No matter how many times I explain it, he won't change his mind.
AnalyzeThe neutral full form is 説明しても.