
Evan R. answered 06/18/19
5 years lived in Russia - married to Russian
Hello, it's actually a fairly simple answer. With the verb учить - научить (to teach) you just have to memorize the format кого - чему? You don't need to think of a literal translation why dative? Isn't it like in the situation мне холодно which means to me is cold? No... There are a lot of times where a direct translation doesn't make sense, you just need to memorize the respective cases.
So in this instance, following the verb учить you must have кого (Genitive) - who and then чему(Dative) - what? For example, the sentence 'teach me something new' would be 'научи(те) меня(Genitive) чему то новому(Dative). In your example, драконов (genitive plural) русскому языку (dative)
Hope this helps!