There are only four named characters in this movie. The two main characters, with the most lines/screen time, are Evelyn and Regan. Regan is a teenage girl, but I would consider her a woman and not just a child character. Evelyn is her mother. They have a few conversations in the first half of the movie about the monsters and their strategy for surviving. The conversations are very short, but they are a comparable length to the conversations between other characters in the movie. They only use sign language, but I think that should count because Regan (and the actress who plays her) is Deaf.