““Then again, it'd taken more than two hundred years after the invention of the scientific method before any Muggle scientists had thought to systematically investigate which sentences a human four-year-old could or couldn't understand. The developmental psychology of linguistics could've been discovered in the eighteenth century, in principle, but no one had even thought to look until the twentieth. So you couldn't really blame the much smaller wizarding world for not investigating the Retrieval Charm.””
