mother land,mother toungh why not otherwise?

The way our school made us understand it, it is this way: motherland, because she has been nourishing her children who all sprang from her bosom, since birth (she is the mother of all the citizens of your country); mother tongue, because it has been the spoken language of everyone from your country counting back to the very first citizen. Where then could have the first person from your country learned the language? It must be from the mother.