They must use this knowledge to further their language development in all areas of language. Also, we cannot simply fill a child's head with knowledge. This is a very hard image to dispel. Each child has to make meaning from what they learn, have it make sense to them and somehow incorporate their understandings into their very own, unique language theories. The theories will develop and become more solid and more 'standard' over time.
Inconsistencies have to be made sense of.
It takes time. Learning occurs like this for everyone in every domain. Outside, in the hallway, are the ideas and theories the children have of the tooth fairy. These are their very own constructions of the phenomenon of a legend, combined with the most important loss of a tooth and the magical appearance of money. Their thoughts have to be taken seriously and respected as they have constructed similar explanations for how this feat is accomplished.