President Trump’s executive order making English the official language of the United States reached into history to argue its case, noting that the country’s founding documents were written in English.

But it turns out, not only in English. After the Constitution was drafted in 1787, supporters of ratification printed translations for Dutch speakers in New York and German speakers in Pennsylvania, so they could understand the arguments for a “vollkommenere Vereinigung” — a more perfect union.

The push and pull over whether America should have one national language or embrace its polyglot spirit has generated fierce debate for more than a century, raising deeper questions about belonging and assimilation in a country whose people speak more than 350 languages.

Now, Mr. Trump’s executive order puts an “America first” stamp onto the nation’s speech.

His order gave a long-sought victory to the English-only movement, which has ties to efforts to curb immigration and bilingual education. Supporters said it recognized the reality of English’s primacy in American life. Nearly 80 percent of the population speaks only English, and immigrants have long been required to demonstrate English proficiency before becoming citizens.

Senator Eric Schmitt, Republican of Missouri, called it a “long, long overdue” official acknowledgment that “in this country, we speak English.” Senator Mike Lee, Republican of Utah, wrote a social-media post in Spanish saying that English should be the country’s “idioma oficial.”

But immigrant-rights groups and congressional Democrats warned that the order could alienate immigrants and make it harder for non-English speakers to get government services, fill out health care forms or vote. The Congressional Asian Pacific American Caucus called it a “thinly veiled attempt to allow federal agencies to discriminate against immigrants.”