Repetition strengthens the connections in the brain in children.
Why is this important? It’s important because the child will learn and notice more and more information during each repetition.
At first, they might just learn the words and melody. Then later on, they might notice what words are on higher notes, interesting things about the rhythm, and so forth. They might even notice rhymes and other interesting patterns. Perhaps this is one reason that the directed listening method works so well!
But it works with every repetition, whether it’s reading the same book every night or watching the same movie dozens of times.
At first, with that book that they want you to read every night, they might notice the story. Then later on, they might see details in the illustrations. Then, still later, they might notice your voice inflections, then later on the emotions in the book.
The learning experience that children have with music is the same. Just learning the song the first time is just the beginning. After that comes the feel of the rhythm, the emotions the song evokes, and eventually, the ability to feel the Spirit testify to them that the words they are singing are true. This level might take time!
Furthermore, memorization, solid memorization, also comes with time. They might be able to sing it from memory early on, but then with more repetition, along with experiencing the song with rhythm sticks or scarves or egg shakers or melody maps or word games, they experience the song in very different ways. These ways help the child internalize the song more and help them understand it at a deeper level.