How we cite our quotes: (Chapter.Paragraph)
Quote #4
For a few days, Mme Raquin could still use her hands, so she was able to write on a slate and ask for what she needed; then her hands died and she was unable to lift up or hold a pencil. All that was left after that was the language of her eyes and her niece had to guess what she wanted. (26.5)
It is interesting here that the narrator tells us Mme Raquin still has the "language of her eyes." Mme Raquin isn't actually able to communicate a great deal through her eyes, so it's ambiguous whether her eyes can be seen as an effective tool of communication.
Quote #5
Grivet had an obsession: he insisted that he had a perfect understanding with Mme Raquin and that she could not look at him without his at once knowing what she meant. That was another sign of how considerate he was – except that, each time, Grivet got it wrong. (26.8)
Grivet's absurd claim of being able to understand Mme Raquin merely by looking at her represents one of the more humorous examples of miscommunication in the novel.
Quote #6
Realizing that her tongue was quite dead, she tried out a new language. By an incredible exercise of will, she managed as it were to galvanize her right hand [...] (27.13)
After Mme Raquin loses her ability to speak, she is forced to adapt to her language loss using other means of communication. Here she tries on a "new language" by forcing her hand to come alive again so that she can scrawl out her message.