Yes, characters can and are developed through dialogue in stories. As your books (or series) goes on, a character may mature in his/her speaking pattern. For instance, if your character at the...
By using the character's: -Thoughts-Appearance-Feelings-Dialogue
the author can develop characters in 5 ways
Characterization
Here are some ways you can develop your character's personality: The way they dress The way they act The way they speak The way they think and feel