Axiom's End by Lindsay Ellis

Description

By the fall of 2007, one well-timed leak revealing that the U.S. government might have engaged in first contact has sent the country into turmoil, and it is all Cora Sabino can do to avoid the whole mess.
To save her own life, she offers her services as an interpreter to a monster, and the monster accepts.
Learning the extent to which both she and the public have been lied to, she sets out to gather as much information as she can, and finds that the best way for her to find the truth is not as a whistle-blower, but as an intermediary. The alien presence has been completely uncommunicative until she convinces one of them that she can act as their interpreter, becoming the first and only human vessel of communication. But in becoming an interpreter, she begins to realise that she has become the voice for a being she cannot ever truly know or understand, and starts to question who she's speaking for - and what future she's setting up for all of humanity.