The English language has conquered by surrendering.

By that claim, I mean that the language has become powerful by adopting forms from other languages.

The greatest problem with making any language required by law is that doing so makes the state the arbiter of what is and is not in the forms of that language, and hence gives the state greater control of those whose thought and expression are dependent upon that language.

The second greatest problem is the violation of the liberty to express oneself in any language that one might wish.

And a further problem is that any language administrated by a formal institution, even if not the state, suffers from the same underlying problem as does an administrated economic system; the administrators simply cannot centralize the information necessary for proper development, and the planned system becomes both chaotic and ossified.