Kim Kohlrus’ 2nd grade classroom is alive with wiggling, chanting children. They’re on their feet, swaying and twisting as their teacher leads them in a call-and-response of letter combinations.

Chelsea Salts, 7, practices with a handset tube during her phonics training. The handset tube helps the students hear themselves as they quietly read out loud. Soon-to-be second-grader Chelsea Salts ...