Schools routinely sort students academically. Classes are organized into grade levels and then further into learning groups. In lower grades, students are often sorted into math groups and reading groups. In higher grades they are separated into courses and classes. But some classes contain noisy and disrespectful students who does not follow the class and school rules very well.
Children in lower grades usually are the most energetic and badly behaved ones in comparison to other grades but usually every class has atleast one student who wants to talk during the classes. The main couse to student become noisy is usually when they meet their friends, wanted to talk with someone, sharing their interests or just having too much energy during the class wich makes teachers very tired after school ends.
In order to properly educate children you need to have quiet classroom so all attention will be on teacher, but there will be always someone who will talk during lessons or giving no attention to teacher, so teachers started to solve this problem by interacting with them. Usually teachers start to raise their voice or making anything loud to take back attention from students to them but that usually scares students and makes them be afraid of teacher and school itself. The best way to interact with children is talk to them quietly, if you quietly and respectfully gain attention from students they will be more open to teachers and by being quiet yourself, you will give them a good example of a good behaviour.
Every school suffers from noisy and disobedience students and not every school trying to properly deal with that problem, but the ones who deal with them in quite and polite way would gain respect from students and everyone around the school.