This quote from “A Report to an Academy” explains how the protagonist can no longer accurately speak about his ape feelings because he can only do so with human words.

Over breakfast, Rosemary learns that Fern was owned by Indiana University. So when Fern was sent away, the Cooke parents had no choice in where she went, and the only thing they could do was send Matt along. Lowell tells Rosemary that their parents did everything they could, but Rosemary is struggling to comprehend this. Lowell says that he will never be able to return to the lab but has someone who gives him updates on Fern. Rosemary learns that Dr. Uljevik greatly disliked Fern. Once, Lowell was able to convince someone to fund getting Fern into a fancy sanctuary, but Uljevik refused to let Fern leave and sent a different chimp, who was almost killed by the other chimps. Thankfully, Uljevik is now retired. Fern has never left South Dakota since she arrived, likely due to her success in giving birth. All of her pregnancies have occurred through artificial insemination, as she does not want to have sex. Lowell considers this rape.