This is the 17498th most frequent Turkish word.
i̇stediği
"İstediği" means "what he/she/it wants" in English.
In this sentence, 'istediği' is used to indicate a specific object that Ali desired or wanted. It's a verb-based relative clause modifying 'kitabı' (the book).
Ali istediği kitabı aldı.
Ali bought the book he wanted.
Here, 'istediği' refers primarily to a wish, highlighting what the subject desired to occur. The expression implies that this wish or desire was fulfilled.
İstediği gerçekleşince çok mutlu oldu.
When what he/she wanted happened, he/she became very happy.
In this context, 'istediği' is used as part of an inquiry about the child's preference or desire regarding the toy in question.