Maybe, since in Portal 1 she makes small grunts when she gets hurt.She can make pain sounds if a cube or something is dropped on her, but no, she does not "talk" in-game.
It could be that she can talk, but doesn't want to grace anyone else (particularly GlaDOS) with her voice. Remember, she is "abnormally stubborn".
Chell might think similarly as Wanderer in The Host (novel by Stephenie Meyer) who refuses to speak when she is first captured so as not to say anything that can be used against her. So Chell probably can talk to but adopts the same attitude.