Command in Spanish Language

I need the advantage of the expert command over the Spanish language, that Don Juan Matus reportedly had, according to Carlos Castaneda.  My perception was that he could say things in precision and exactitude, and that his vocabulary was quite extensive, including many ways of saying the same thing.  His idiom was not peculiar to him, but it was particular to his range of readings.  He could use the equivalent of an equation, and was able to expand it into meaning not just the literal meaning, but also the meaning of an expression. He could say something in the idiom that he had borrowed from books, instead of using the cultural idiom of his times. He could construct meaning out of nothing.  He could say a familiar saying in a way that made it original to him.  He could say something that no one had said before, but sounded familiar and true.  His vantage point gave him extreme ability and latitude in speech.