Which of the following is NOT typically a role of a sound mixer in film production?

The role of a sound mixer in film production primarily involves working with audio elements, which includes balancing audio levels, recording dialogue, and sometimes creating sound effects. Balancing audio levels ensures that the various elements of sound in the film—such as dialogue, music, and sound effects—are at appropriate volumes relative to each other, allowing for a clear and immersive audio experience. Recording dialogue is essential as it captures the spoken words of the actors, which is a key component of the film's narrative.

Creating sound effects is also part of the sound mixer's role, particularly when it comes to integrating these effects into the film’s audio track. However, editing the script falls outside the responsibilities of a sound mixer. Script editing is a task typically handled during pre-production by writers or script supervisors who focus on the narrative and dialogue written for the film. Therefore, it is correctly identified that editing the script is not a typical duty of a sound mixer in film production.