The phrase "school language" refers to the type of language used in educational settings, like schools. It includes words and phrases that are commonly used in classrooms and textbooks to teach topics and ideas. Full definition
In a former life, I was a middle school language arts teacher. (edutopia.org)
For example, 5th and 6th grade math teachers might work on strategies for teaching word problems, and middle school language arts teachers might collaborate on evaluating student writing. (ascd.org)
I am a former high school language arts teacher who has been working in education research since 2005. (edutopia.org)