Questions & Answers about Bu çantayı sana aldım; güle güle kullan.
Because çanta is the direct object of the verb aldım and it is a specific, definite object: this bag.
In Turkish, definite direct objects usually take the accusative ending. So:
- çanta = bag
- çantayı = the bag / this specific bag as the object
So Bu çantayı aldım means I bought this bag, not just I bought a bag.
The -y- is a buffer consonant.
The noun çanta ends in a vowel, and the accusative ending here is -(y)ı. When a vowel-final word takes a vowel-initial ending, Turkish often inserts y to make pronunciation smoother:
- çanta + ı would be awkward
- so it becomes çanta-y-ı
This happens a lot in Turkish.