The Language of Liars

Ro is a spy in training for a small civilization whose resources are dwindling and whose reach is shrinking. His elders send him to jump into the mind of a Star Eater, a member of the only species physiologically able to mine the element that makes lightyear-spanning space travel possible.

The Star Eaters have shared very little about themselves, and Ro's people badly need to know more. Ro has studied their species all his life. He admires and respects them, and he is reverent at the thought of becoming one of them. The jump itself depends on a moment of perfect psychic connection.

His elders warn him that the experience will feel real and never be real, and that a spy always lives a lie. Ro is certain he will be the exception. He believes his heart will belong to the Star Eaters, so he will not be an impostor hiding his past.

This is science fiction built on body jumping, secrets and linguistics, with language as the way into another people's minds. Learning to speak as the Star Eaters do means knowing them and becoming them, and Ro never considers that understanding could harm the people he understands. The book is by S. L. Huang.