In a nation made up of many different people’s of a diverse background, having a shared national language is even more important.
We have this myth of assimilation, as though it is a powerful force that always happens to any group which comes into a country. That isn’t true at all. The USA was able to assimilate a number of peoples from various countries, though it didn’t always work. People from white and primarily Christian nations did tend to assimilate, but for others there has been more trouble. We still have China Towns, we still have communities of Hasidic Jews who speak Yiddish, we still have the Amish, we still have a massive cultural and political gulf between white and black America, and in recent decades we have growing Hispanic enclaves in various US states. In Europe, there are ethnic/national groups that have failed to assimilate despite living among another nation for longer than the USA has existed.
So assimilation is hard and takes work, even then it’s hardly a sure thing. It’s especially not a sure thing when one side of the political aisle (the side who also happens to almost completely control the media, entertainment, and education) fights tooth and nail to prevent assimilation and to fan the fires of ethnic division within new arrivals. With immigrants of the past, not only were they more racially and culturally similar to the WASP they were living among, but they had a huge impetus to assimilate. Now, the message that immigrants get isn’t that America is great and that they should assimilate and be a part of of America.
This is the message they get:
No borders and America was never great. If your home country was poor, it is because of the USA and white oppression, you can come here and get some of the money that is rightfully owed you by white America. Our immigrants, for the most part, don’t want to be Americans and the Americans who have the most influence over immigrants (the left) don’t want them to think of themselves as Americans either.
Leftists may hate White Nationalists, but they do have one major belief in common: they both believe that the USA is a white man’s country and that non-whites (people of color as they say now) aren’t real Americans. Of course, the WN’s think that this is a good trait of America and the SJW’s think that this is a bad trait of America. But the SJW’s have the power now to exacerbate the ethnic and cultural chauvinism of immigrants into a political force that ultimately will bring down the USA when we reach a point where the majority of people living in the USA don’t see themselves as Americans but as a distinct ethnic and/or cultural group at odds with America. That is why this massive wave of immigration is so dangerous, along with the way it is being exploited by the identitarian left. Because as identity politics becomes an increasingly dominant part of the American landscape; issues of rights, economics, defense, and general welfare fall to the wayside - as we already see happening. We especially see this happening within the Democratic Party, where their traditional political values are becoming secondary to identity politics and fomenting hatred and discontent among their coalition of the supposedly oppressed - their scapegoat being white, straight, Christian men.
For America to survive, it must be a nation and not an empire. We must have a shared sense of ourselves as a single people with a common history, common values, and common interests. This is what America must be to survive, this is what every nation must be to survive, and this goal is directly at odds with both the agenda and the consequences of massive and unlimited immigration.