Breakdown of Onların hatası yüzünden kapı açılmadı.
kapı
door
onlar
they
hata
mistake
açılmak
to open (intransitive, be opened)
Questions & Answers about Onların hatası yüzünden kapı açılmadı.
Could we use 'için' instead of 'yüzünden' here?
You could, but yüzünden is much more precise here. It specifically means 'because of' with a negative result, often implying fault or blame. Since the mistake caused a bad outcome, yüzünden is the most natural choice.
Why is it Onların hatası yüzünden instead of just Onların hata yüzünden?
Yüzünden acts on completed concepts. First, you have to build the phrase 'their mistake,' which is a standard possessive compound: Onların (their) + hata-sı (mistake). Once that phrase is built, you simply place yüzünden right after it.
Since the pronoun is plural (onların), why isn't it hataları?
Because the pronoun onların is explicitly stated, Turkish speakers often drop the plural possessive ending and just use the singular -sı ending when referring to a single, shared thing. Both Onların hatası and Onların hataları would be perfectly correct here.
What does the -ıl- do in the verb açılmadı?
The suffix -ıl- makes the verb passive. The base verb açmak means 'to open' (as in a person opening something). By adding -ıl- to make açılmak, it means 'to be opened' or describes the object itself opening. So kapı açılmadı means 'the door did not open'.