Okay, so let's pretend that you're playing with some toys and you have this really special toy that is like the main toy. But you also have some other toys that are not as special, but still important to the game. That's kind of like what Nebenstimme means in music.
When a composer writes music, they have a main melody that is like the special toy. But they also need other parts to support that melody and make the music sound complete. These supporting parts are called Nebenstimme. They might be playing a different melody or just helping to make the main melody sound even better.
Think of it like a big group of friends playing together. One friend might be the leader and have the main idea for what they want to do together. But the other friends also have great ideas and can add their own little parts to make the whole game even more fun.
So, Nebenstimme is like the supporting friends in music, making sure the main melody sounds awesome and complete.