The planet Ixchel is named after the Mayan goddess of the rainbow and patron of medicine. The name is appropriate because Ixchel, like the Biblical rainbow of the Noah's ark story, gives Meg the opportunity to rehabilitate, even though the planet is devoid of color. The beasts act as medics, restoring Meg's health after her dangerous encounter with the Dark Thing. In Chapter 11, L'Engle challenges our fundamental assumptions about how people interact with each other and perceive the world. Mrs. Whatsit had told Calvin that his gift was his ability to communicate with all types of creatures. Calvin's gift proves useful as he struggles to explain their situation in a language that the beasts can understand. The beasts do not understand ordinary speech. Their words are spoken through their tentacles in an entirely different language. Aunt Beast tells Meg that her language is "so utterly simple and limited that it has the effect of extreme complication". Most of the wonderful things on Ixchel cannot be described in words. Aunt Beast's singing is "impossible to describe to a human being". She feeds Meg "something completely and indescribably delicious". She tells Meg that she has great difficulty expressing things the way her mind shapes them. Aunt Beast is uncomfortable with human language and it is evident from her grammatical and syntactic irregularities, such as "Would you like me to take you to your father and your Calvin?"
Chapter 11: Aunt Beast
The beasts have a great ability to read Meg's thoughts. For example, Aunt Beast's mind can read Meg's mind as she thinks of possible names for her. This type of extrasensory perception is similar to Charles's ability to know Meg's thoughts, a well as the ability of the Man with the Red Eyes to read into the children's minds. In segregating verbal speech from communication, L'Engle elucidates that language is only one possible way of relating to one another. Similarly, by separating sight from perception, L'Engle shows that seeing is only one way of coming to know and understand the world. When asked to explain the concepts of light and sight to Aunt Beast, Meg realizes how much her sense of the world is informed by vision. This lesson is repeated later when Meg must describe the Mrs. Ws without referring to their physical appearance. The mismatch between sight and perception functions to reinforce one of the novel's major themes, the relationship between appearances and reality. Aunt Beast tells Meg, "Think about things as they are. This look doesn't help us at all". The difference between form and essence is also relevant to the type of food that the beasts serve Calvin and the Murrys. Unlike the food on Camazotz, which looked delicious but tasted like sand to Charles, the food on Ixchel is gray and dull but tastes indescribably delicious. By scripting a planet where perceiving does not mean seeing and communicating does not mean speaking in words, L'Engle effectively establishes the primary themes of her novel.