All of the house-elves were on strict orders not to communicate with Hermione until after breakfast and even then they had to have a certain phrase said to them by Lucius before they could talk to Hermione. The house-elves were under the impression that Lucius was kind to Hermione, when in fact that was the opposite of what was going on but she knew that things would become worse if she ever spoke a word of what their precious master did to her.