LE GUIN, Ursula K.
The Word for World is Forest

Captain Raj Lyubov had a headache. It began softly in the muscles of his right shoulder, and mounted crescendo to a smashing drumbeat over his right ear. The speech centers are in the left cerebral cortex, he thought, but he couldn't have said it; couldn't speak, or read, or sleep, or think. Cortex, vortex. (...)

Published by Gollancz, 2014 (1972)
Science/Fiction