てる・ てた・ てます・ てましたConversational contractions of ongoing and resulting states
In conversation, the い in ている and でいる is very often dropped. The shorter form keeps the same meaning, tense, negative status, and level of politeness as the full form.
How the contraction works
First make the full form, then remove only the い. After that, the remaining る changes normally for past, negative, or polite forms. For example, 書いている becomes 書いてる, and 読んでいた becomes 読んでた.
The meaning comes from the full form
The contraction itself adds no new meaning. Expand it back to the full form and interpret that form in context: it may describe an action in progress, a resulting state, or a habit.
Past, negative, and polite forms
Dropping the vowel does not erase the distinctions carried by the ending.
Do not confuse it with the preparation contraction
The short forms taught here come from ている or でいる and describe an ongoing action, state, or habit. By contrast, とく and どく shorten a different construction and commonly express doing something in advance or leaving it in a useful state.
More examples
弟は今、シャワーを浴びてる。
My younger brother is taking a shower now.
Analyzeこのパソコン、壊れてるみたい。
This computer seems to be broken.
Analyze最近、毎晩日記を書いてる。
Lately, I've been writing in my diary every night.
Analyze朝から何も食べてない。
I haven't eaten anything since this morning.
Analyzeさっきまでそこで待ってた。
I was waiting there until a little while ago.
Analyze先生はもう教室に来てます。
The teacher is already in the classroom.
Analyze子どものころ、この公園でよく遊んでました。
When I was a child, I often played in this park.
Analyze