Breakdown of Bu otomatik kapı kendi kendine açılıyor.
bu
this
kapı
door
açılmak
to open (intransitive, be opened)
kendi kendine
by itself / by oneself (also: kendi kendime, kendi kendimize)
Questions & Answers about Bu otomatik kapı kendi kendine açılıyor.
Why does the second kendi in kendi kendine take an -e ending?
In reflexive reduplication, the first word stays bare (kendi), while the second word takes a possessive suffix and a case ending. Because the door is third-person singular, the second word uses the third-person possessive (which is absorbed into the final vowel of kendi) plus the dative case -e. The -n- is a buffer letter used before adding case endings to third-person pronouns. Literally meaning 'itself to itself', this structure translates as 'by itself' or 'on its own.'
Why use the verb açılıyor instead of just açıyor?
The base verb açmak is transitive, meaning 'to open [something].' If you wrote kapı kendi kendine açıyor, it would sound like the door is opening something else! To say that the door itself is undergoing the action of opening, you must use the passive/middle-voice form açılmak (to be opened / to open).
If I wanted to say I opened the door 'by myself,' would I still use kendi kendine?
No, the reduplicated phrase must match the subject. If you (first-person singular) did it by yourself, the second word takes the first-person possessive -m, becoming kendi kendime. For example: Kapıyı kendi kendime açtım (I opened the door by myself).
Does kendi kendine always mean 'by itself' or 'on its own'?