This is from the movie "Room" based on the novel of the same name by Emma Donoghue. You can find it at 1:47 (one hour forty seven minutes) into the movie. When I saw it, I was floored. So poetic, beautiful and simply written which made it all the more powerful. Imagine being a child who grew up in a room the size of a garden shed, who never saw the outside world. Based on events in the news where women and their children were held captive for years but a fictionalized account. The screenplay was nominated for an Academy Award for best writing, adapted screenplay and for a Golden Globe best screenplay - motion picture category. It's star Brie Larson won best actress at the Oscars and Golden Globes. The movie is straight up moving; if you don't get teary eyed watching it you're clearly an android sent fro the future to destroy us, hehe. The monologue I'm recommending from this film is an amazing snippet that could be a very moving performance for a young actor auditioning for a drama. Vulnerable, sweet, innocent, yet wise. The child actor should be able to play approximately five years old, though I think you could have an older child perform it and it would still be very moving and effective up to about 10 years old. You watch it and see, the film is available streaming on the various video services or you can get it here.
Start the monologue at 1:47 in the movie (right toward the end of the film) with the line "When I was 4, I didn't even know about the world ... and now me and ma are going to live in it forever and ever until we're dead." and you can end it just under one minute long with the line "Because it's still just you and me." Alternately, you can extend it a little longer and end with "Bye Bye Skylight ... Ma, say bye bye to room" at 1:52.