this part is wrong, because each country has his own Institute to say which word is correct and wich not, so it is not the same language in spain or in Argentina, for example
http://www.asale.org/academias
they exists even in non spanish talking countries as USA, Puerto Rico or Philipines ...
RAE > Academy
The local academy know all about the spanish in their country, like their history, evolution, etc; it's a kind of local control. The RAE is who regulates the spanish for all of us. (or do you imagine the RAE explaining about local evolutions of the spanish?)
The spanish is the language (or the Castilian) , the kind of spanish that you speak in Spain, in Argentina, in Peru or in Chile is a dialect.