"It is obviously a delicate matter to discuss the fine line between embracing and welcoming a variety of 'others' to enhance one's society and knowing when and HOW to ask 'others' to please try to adapt to the customs and language they are visiting or emigrating to."

That sounds scary. Why should anyone need to "adapt" to customs and language??

One of the beautiful things about the US is that we do not have an official language and no one needs to "adapt" to anything other than the laws.   Sure, it can be frustrating when you run into a clerk that does not speak English, but so what?   If you stop to think, you probably learn something from such interactions.