Answer:
It creates suspense as the reader wonders why the narrator can no longer hear Doodle's voice.
Step-by-step explanation:
The short story "The Scarlet Ibis" by James Hurst tells the story of Doodle, a handicapped boy, and his short life that he lived with his family, especially with his brother. Though narrated by the protagonist's brother simply called "Brother", the whole plot revolves around the life of the little boy William "Doodle" Armstrong.
Foreshadowing is a literary device used by writers to give an idea or hint about what might happen in the next upcoming scenes/future. The author of this short story uses foreshadowing in the line "Soon I could hear his voice no more". This predicts the upcoming scene where "Brother" couldn't hear his voice, giving us a feeling of suspense in what was to happen/ what had happened to Doodle.