Why didn't Melody warn her mother about Penny being near the car?

Melody didn't have her Medi-Talker, so she could communicate properly with her mother to warn her that Penny had slipped out the front door.

Melody did warn her mother about Penny being behind the car but, her mother was already annoyed enough that she didn't pay attention to what Melody was really saying. She was in a foul state already and you could even see that Melody thought she was too. Melody cried and kicked but her mother paid no attention and flung her arm off of her so she could continue backing up the car. That's when Melody's father came out and asked where Penny was and when suddenly both Melody and her mother felt a bump under the car.