Dialogue – Rick’s line “Of all the gin joints in all the towns in all the world, she walks into mine.” is effective as it tells the audience how certain he was that he’d never see Ilsa again, therefore he speaks in a shocked manner after she comes to his cafe.

Underscoring – A soft but noticeable piece of music accompanies the scene where Rick uses a gun to threaten Renault, building suspense and audience intrigue as to whether he will actually shoot him.

Sound Motif – The song ‘It had to be you’ recurs throughout the film as a reminder to the audience that Rick and Ilsa’s relationship was real and impacts their behaviours in the narrative of the film. The song is heard for the entirety of the Paris flashback, as this is when Rick and Ilsa’s love for each other was the strongest.

Synchronous Music – Synchronous music can be heard in the scenes taking place in Rick’s bar, with Sam playing the piano and singing to customers. Even when the attention is on other characters, the music continues to maintain the verisimilitude of the film.

Sound Mixing – In the scene where the plane is beginning to land in Casablanca, a musical score can be heard in addition to the sound of the plane flying and dialogue. These being heard all at once establishes the atmosphere of the scene and creates a sense of realism.