This is the 17074th most frequent Turkish word.
çevrelerindeki
"Çevrelerindeki" means "in their surroundings" or "around them."
In this sentence, 'çevrelerindeki' is formed from 'çevre' (environment/surrounding) and the possessive suffix '-leri' plus the locative suffix '-ndeki', indicating possession and location in relation to the subject 'the children'.
Çocuklar çevrelerindeki çiçeklere dikkatle bakıyor.
The children are looking carefully at the flowers around them.
Here, 'çevrelerindeki' relates to 'çevre' (environment/surroundings) possessed by 'authors', showing where the events being described occur.
Yazarlar çevrelerindeki olayları kitaplarında anlatır.
Authors describe the events around them in their books.
'Çevrelerindeki' specifies the origin of the sounds, relating them to the surroundings of the patients with possession and positional context.