A girl sits by herself and cries out in pain, but nobody hears her. She is surrounded by her "demons," which the poem seems to use for inner struggles like despair or mental suffering rather than anything supernatural. The speaker watches from the outside and asks a desperate question: why won't anyone break through the "sound barrier"? That phrase suggests an invisible wall between the girl and everyone else. Her pain is loud to her, but silent to the world.
The mood is bleak and helpless. The short, plain lines feel like someone speaking quietly and wearily. The speaker seems frustrated at the people who don't notice, yet the last lines turn toward something harder to accept. "How can you save someone / From their inner demons?" admits that even if someone did hear her, rescue might not be simple. The poem ends on a question with no answer, leaving us with sadness and a sense that some battles are fought mostly alone.