New Jersey's largest teacher's union has gone to court to close a Newark charter school where students spend hours each day in front of a computer screen.

A computer voice guides 12-year-old Amir Accoo to spell the words he hears through his headphones: emergency, bulldozer,  minutes. Accoo spells minutes wrong and is asked to try that one again, several times. Later, he clicks on a proofreading button.