This week, MTV launched a new channel, “MTV Three,” aimed at young Latinos. Unlike the former “MTV en Espanol,” “MTV Three” shows will almost all be in English, it being the language that speaks most directly to Latinos between 12 and 34.

This puts me in mind of the English Only movement and other efforts by people convinced that English needs to be declared “official.” These people are devoting time and energy to a problem that does not exist.

Human beings surrounded by a language from birth learn to speak it fluently. This includes not only the language of their family, but others they encounter in the wider world, at school and in the media.

It has been ever thus. The first immigrant generation often only learns to “get by” in English. Their children are bilingual. Then their children likely don’t speak their grandparents’ language except for some words and expressions. Irving Berlin’s mother never learned English. He spoke Yiddish and English and his daughters spoke only English.

As such, most of “MTV Three’s” viewers speak Spanish as well as English, but if there is a language under threat, it’s Spanish. Their Spanish is usually “Spanglish,” full of English words to the dismay of their elders. Even people as isolated and wary of outsiders as the Amish speak fluent English alongside their Pennsylvania “Dutch” German dialect.

English Only advocates are making an understandable American mistake. English happens to be the only language here that is passed down the generations on a large scale. Americans, then, often do not spontaneously grasp that speaking one language at home and another one when out and about is not an exotic or fragile condition, but a human norm.

After all, there are about 6000 languages and about 200 countries — do the math. Typically, a country has scads of obscure local languages and then an official language or two that most people speak alongside their home ones. To take two countries currently making news, Iran and Thailand are both home to about 75 languages.

Yet Persian and Thai are doing just fine. Spanish is not “taking over,” but taking its place as a home language like the little-known ones in Iran and Thailand.

It is also easy to forget that America too has always been a linguistic cacophony. In the 1800s many big cities had several daily German newspapers. A preface to an 1834 book told us that for the man on the go, German would “greatly facilitate his intercourse with a very valuable part of our population.” One writer had it that in Lower Manhattan after dark “The US language is a hard find” — in the late 1800s.

Yet English Only advocates seem to see Spanish today as a different case. They sense, I think, that today’s Latino immigrant often has a different relationship to English than Irving Berlin did. The gaslight-era immigrant did tend to embrace learning English and “becoming American.” And it is true that today, identity politics discourage many of today’s Latino immigrants from this kind of openly avowed allegiance to the language of the gringo.

Yet there is a difference between superficial attitude and the reality of how human beings learn and use the languages around them. The simple fact is this: even if Latinos wanted to discard English as the language of the oppressor — which they do not — they couldn’t. Their children would learn English regardless, unless raised in a closet and fed through a slot.

As such, Republicans’ obstructing the renewal of the Voting Rights Act a few months ago with their proposal to eliminate foreign-language ballots was a sad moment. There have always been plenty of first-generation immigrants in America whose English was approximate, such that dealing with the technical language on a ballot would be tough. Political language in a foreign tongue would hobble many Americans, even educated ones, and even after having been in the country only a year or two.

If we pride ourselves on being an immigrant nation, then we should have no problem with people voting as Americans in the languages they were born to, just as we do not begrudge them their foods or music. Their abbreviated ability in English has never been, and is not, a threat to English as the language of our land, because their children will speak it like we do. The reader may very well be married to one of them.

I stress this not as a mere matter of speaking up from the Halls of Linguistics Ivy. While the English Only philosophy stems from an understandable lack of clarity on how languages coexist in human societies, it bears mentioning that in college classrooms across the nation, English Only writings are held up as evidence of the persistence of bigotry in America, which is an enabler of, for instance, the charge that Republicans are racists.

Calls to make English an official language condemn the inevitable — how hard it is to learn a language well after about 13. What is being called for already exists — namely, people raised in an Anglophone nation learn English. Movements treating English as a threatened tongue in America should be laid to rest.

Mr. McWhorter is a senior fellow at the Manhattan Institute.