I have been thinking about the difference between the job titles, Teacher’s Assistant (T. A.) and Assistant Teacher (A. T.). When you look at it through the lens of the adjective noun structure of the English language it looks like this:
Therefore, a T.A. is an assistant and the adjective that describes their role is that they are an assistant to the teacher. An A.T. is a teacher and the adjective that describes their role is as an assistant teacher. These are terms that seem to be batted around as synonyms. I think the difference would play an important, albeit implicit, role in framing the practices between the T.A./A.T. and the teachers.