The US Constitution isn't about creating a world government. If the rest of the world adopted the US Constitution or something very similar, there wouldn't be immigrants flooding into the US.
The only way Mexico will ever be respected, and Mexicans as a result would be respected is to make their own country a decent one. I don't think Mexico should give up their language and culture just like I don't think the US should ---but if Mexico changed it's political and economic system, it wouldn't be a hellhole everyone wants to leave. At one time Japan was ridiculed and their products were mocked until they actually built themselves up ---and it wasn't by forcing other countries to take their citizens. Now they are competitors of the US and respected for what they can do. There is no excuse for Mexico with it's vast land and resources not to do more for it's people.
We have a winner here...that's the key issue as always - and the way for Mexico to do that is to adopt some of the basic principles embodied in the Constitution, property rights, limited government, and rule of law. It should also be pointed out that these things exist for the middle class in Mexico but not for anyone else.