Which technique involves the use of a narrator's voice to give insights into a character's thoughts?

The technique that utilizes a narrator's voice to provide insights into a character's thoughts is voice-over. This method allows filmmakers to give the audience access to a character’s internal monologue, making it possible for viewers to understand their motivations, feelings, and conflicts that may not be apparent through dialogue alone. Voice-overs can enrich the narrative by adding depth to character development and enhancing the viewer's emotional connection to the story.

In contrast, dialogue refers to spoken exchanges between characters, which primarily serves to advance the plot and reveal information through interactions. Diegetic sound is any sound that originates from within the film's world, such as characters speaking or environmental noises, and does not typically include internal thoughts. Scriptwriting is the process of writing the screenplay, encompassing dialogue and stage direction, but it does not specifically refer to the narration of a character's thoughts. Thus, voice-over is the correct term for the technique that provides these unique insights to the audience.