As with their parents, children are often caught in some no-man's-land
between home speech patterns and the standard forms of the school. Many
features other than purely linguistic or sociolinguistic ones are relevant here.
First, recall the notion that the school may be seen as essentially feminine by
children whose native culture is one stressing action, immediacy, etc.
Second, bear in mind that the school and the teachers are seen as outposts of
authority, and that different social groups react to authority in different
ways.