On linguistic dreams

A correspondent writes to tell me of a linguistic dream he just had. As follows:

'I had a dream the other night with Significant Linguistic Content. It started out as the standard nightmare (mercifully infrequent these days) that I was teaching in a secondary school, as was the case long ago. But things improved and softened: the kiddies (11-year-olds, I'd say) were nice, and their music teacher, a fiftysomething German lady, came in and asked me would I mind if they practised the song that ...