Imagine this Gedankenexperiment, if you will: a class of tenth-grade EFL students working in groups are, while completing the task, either speaking English or not speaking English. Until the teacher moves closer to supervise their work, the students must be considered in a state of quantum superposition, in which the states of "speaking English/following directions" and "not speaking English/ignoring directions" overlap. It is therefore the observation of the teacher itself which affects classroom behavior and forces the students into a definite linguistic state.
(ps: I know this isn't really quantum theory at all. It should involve decaying nuclei and radioactive substances, but, much as I occasionally wouldn't mind forcing the students into a dead state, I don't think the principal would look kindly on hydrocyanic acid in the classroom.)
(pps: I'm kidding. I would never kill my students. I love the little brats dearly, even when they are in the state of "not speaking English/ignoring directions.")