Another fun one on this example is somebody after coming out of a coma being effectively fluent in a foreign language. Obviously the person had to have at least some familiarity with it before, but there are countless cases where somebody goes from knowing a few words of a language (presumably having forgotten everything they learned in school or whatever) to suddenly speaking it, more or less, fluently. Similar incidents can also completely change a person's accent and have other such interesting effects.

There's almost certainly some way to tap into this without (what is usually/always) brain damage, which has interesting implications for the long-term future of education.