This is the 1429th most frequent Turkish word.
erdal
"Erdal" is a Turkish male given name, meaning "mature" or "wise man."
Here, 'Erdal' is used as a proper noun referring to a person.
Erdal çok çalışkan bir öğrencidir.
Erdal is a very diligent student.
In this sentence, 'Erdal' is again a proper noun, referring to the source of information, which is Erdal.
Bu sorunun cevabını Erdal'dan öğrendim.
I learned the answer to this question from Erdal.
The usage of 'Erdal' in this sentence denotes the topic of discussion, which is the person named Erdal.