That is pretty simple it is someone who will read to the student everything that they are assigned to do. For example some students have "human reader for tests and quizzes." This means that the students have a human reader for the tests and quizzes, but in the classroom they read on their own. Then you have the students that have human reader for everything, some teachers will try to push the students to try and read, but it is extremely difficult.
As always please let me know if you would like me to write about anything?