Equal but separate.

ENGLISH is the language of most Americans, and for the last two centuries it has been the key to an immigrant's economic success. Yet today we are on a path toward becoming an officially bilingual nation.

In Florida, Spanish-speaking residents are increasingly demanding government services in their native language. In California and Texas, Spanish-language advocates like to observe that this land was Spanish before it was English. Last year in Tucson, the Immigration and Naturalization Service swore in a batch of new citizens in Spanish. We spend $10 billion each year on bilingual education, with the bulk of it spent, not teaching English to immigrants, but teaching course work in native languages.

To find out how bad things can get, I recently traveled to Brussels for a two-day session with an assortment of proponents and opponents of official bilingualism. Belgium is one of the countries that supporters of bilingualism hold up as shining examples of how peoples of different languages and diverse cultures can be held together through a federalist system that asks no one to assimilate.

To understand present-day Belgium you must understand the country's history, and you must keep a scorecard. In 2002 Flemish-speaking Belgians will celebrate the seven-hundredth anniversary of the Battle of Flanders, in which their forebears defeated the French. Five centuries after that battle the Flemish, with much help from the English and Prussians, witnessed the defeat of Napoleon at Waterloo. Today the Flemish, who number about six million, or 60 per cent of Belgium's population, live in the northern part of the country. The French-speaking Walloons reside in the south. The border between the two has for centuries been the invisible line dividing Germanic culture to the north from Latin culture to the south.

In 1963 this line was codified by the first in a series of language laws. No problem, you say. The Flemish stick to their neighborhood, and the Walloons stick to theirs. But there is a problem: Brussels, the country's largest, richest, fastest-growing city, the capital of post-Maastricht-Treaty Europe. The only officially bilingual region of Belgium, Brussels is more than 85 per cent French-speaking, and it is located in the heart of Flanders--a French island surrounded by a hostile Flemish sea. The 1963 language laws allowed some 19 communes (suburbs) of Brussels to offer government services in either French or Flemish. Today most of these communes have French-speaking majorities. Yet the mayors must be able to speak Flemish; after all, they're in Flanders.

Brussels is a bilingual mess. Mail can take more than three days to reach one side of the city from the other. Mayors fight with regional councils, which fight with federal officials, who fight with everyone. On one block in the city you'll receive only Flemish cable TV. Around the comer, you'd better speak French. The costs of maintaining this bilingual artifice are daunting. But when I asked representatives of the Flemish, Francophone, and Federalist parties if they were concerned about the country's debt, more than 140 per cent of GDP, the replies boiled down to: "Translators are cheaper than guns."

The new federal system, which doles out proportional legislative representation based on a language-quota formula that would take a hundred pages to explain, is being given a chance to work by both sides--for now. Notes one Flemish journalist, "If we could, we'd separate today. Brussels is the problem, and so is the cost of Social Security that flows from the wealthier north to the poorer south. But you can be assured that we will never give up Brussels. And we will not allow any further expansion of the commune facilities--those towns that allow the spread of French-speaking areas."

"They stole our industry, and now they refuse to acknowledge that they have a responsibility to the Walloons," says a representative of the Francophone party. "We will continue to press for the rights of the French-speaking community and the expansion of the commune facilities."

When I asked a professor from the Federalist party, which takes a middle-of-the-road position, if he thought Belgium's method for dealing with the different ethnic/linguistic groups should be used as a model for a new united Europe, he nearly choked to death on his croissant. But he noted that Israel has asked the Belgian government for help in managing diversity on the West Bank.

What does this all mean for America, the land of immigrants, the home to more than three hundred different languages? According to everyone I spoke with in Brussels (and everyone I met at a similar gathering in Quebec last January), it means: You'd better protect the language that unites your country, because if you don't you could end up like us, or worse.

"You mean we shouldn't proceed down the bilingual English/Spanish road?" The response was unanimous: absolutely not.

There's nothing wrong with diversity. I actually wish I could speak more than one language fluently. But in our nation, English is the key to understanding. It puts immigrants on the same plane with fifth- or twelfth-generation Americans.

I have seen the future of official bilingualism, and it is not far away. Under a veil of political correctness, we are slowly creeping toward the day when our government does what Canada did under Pierre Trudeau--make two languages equally official. We're not Belgium. Nor are we Quebec. But the signs are there. At least they're still in a language we can understand.

Mr. Mosier, an advertising copywriter and essayist, serves on the board of directors of U.S. English.