One in five United States residents now speak a language other than English at home.

That was the headliner coming out of a report released this month by the Center for Immigration Studies. The report is based on data from the 2013 American Community Survey that shows those speaking a language other than English reached a record 61.8 million, roughly 21 percent of the population.

By comparison, in 1990, 14 percent of U.S. residents fit that category and in 1980 it was 11 percent.  (The “resident” category includes native-born, legal immigrants and illegal immigrants residing in the U.S.)

Considering the Obama administration has little respect for our immigration laws–deporting fewer illegal immigrants than any administration since the early 1970s and, via executive fiat, giving amnesty to millions already here illegally with a threat to do more of the same after the mid-term elections–Americans are right to worry we have a problem.

But this survey shows it may extend beyond the one you think.

As my Heritage colleague Mike Gonzalez, (also the author of an excellent book, “A Race for the Future: How Conservatives Can Break the Liberal Monopoly on Hispanic Americans”), explains, the problem is not what language Americans speak around the kitchen table.

As a nation of immigrants, America has always had a high percentage of foreign-language speakers. German and Dutch speakers by themselves may have come close to 10 percent of the population in the late 1700s and there were of course several Native American languages spoken in the 13 original colonies. The problem is more the importance of a common language in the public sphere, something which the health of our republican form of government requires.

But ensuring America maintains a common language in the public square means everybody who lives here, regardless of what they speak at home, has to learn to speak, read and write English.  Promoting bilingual programs in schools and offering voting ballots and other government documents in multiple languages may be politically correct but it is a disservice to both the country and the people those promoting such measures say that want to help.

And indeed, the survey findings support that.  Of those who speak a language other than English at home, 25.1 million (41 percent) said they speak English “less than very well.”

More troubling is what the survey shows about assimilation. For many, it does not appear to be happening:  “Of the nearly 62 million foreign-language speakers, 44 percent (27.2 million) were born in the United States.”

Being able to speak two or more languages is certainly a good thing and often an advantage for those who possess that skill.  But when “bilingual” or “multilingual” means a country where multiple languages are spoken by different groups of people, you get the United Nations, not the United States, and there is nothing “united” about it.

One of America’s greatest strengths is that we are a country made up of cultures from around the world– even our motto, “E Pluribus Unum,” means “Out of the many, one.

But we cease to be “one” if we have few things that unify us beyond where we live. The more multicultural America becomes, the more important it is we are all able to communicate with one another.