A new study finds that people match each other’s language styles more during happier periods of their relationship. Even famous poets who were married exhibited this effect in their poetry, the study found.

The tendency to mirror our voice to that of our conversation partners is called “language style matching.”

“When two people start a conversation, they usually begin talking alike within a matter of seconds,” said James Pennebaker, a psychology professor at the University of Texas at Austin and an author of the new study published in the September issue of the Journal of Personality and Social Psychology. “This also happens when people read a book or watch a movie. As soon as the credits roll, they find themselves talking like the author or the central characters.”