What is it? The English language, of course.
In Europe, it's everywhere, especially as the 1 May date for enlarging the European Union draws near.
The Germans resisted it for a while but, mostly, have given in. The French still are fighting a rearguard action against it. Agence France Presse reports that French-language aficionados are actively promoting French speech at EU headquarters in Brussels, offering free lessons for newly arriving EU officials and diplomats. The idea, as AFP puts it, is "to ensure that the language of Moliere doesn't get left out."
But, AFP reports, even at the EU -- where nearly everyone is multilingual -- English increasingly is the default language in any gathering of more than a few people. Agence France Presse ought to know. The French news service distributes its news report in English as well as French.
Dana LeBherz, country manager of instruction in the Czech Republic for the language giant Berlitz, says record numbers of people are learning English -- not for convenience any more as they used to but out of necessity.
"It's become more and more important because of the extension of the EU. Before it used to be a tourist language and now it will become necessary for government, for industry. People who want to advance in their careers will have to speak a certain level of English," LeBherz said.
With 25 countries after 1 May, the EU's language task will be immense. The number of possible combinations in language interactions will grow to nearly 400. EU translation chief Karl-Johan Loennroth, in mock terror recently, urged a seminar to find him someone who can translate from Maltese, the tiniest official language in the EU, to Finnish, perhaps the most difficult.
The cost of the EU's translation services will go from 500 million euros ($603 million) a year to 800 million euros.
Eric Mamer, spokesman on administrative reform for the EU executive, the European Commission, says it's not a problem. He says the EU simply will use the solutions that it has been using all along -- only more so. For example, what to do about Maltese-Finnish: you use a transition language, Maltese-English, English-Finnish.
"It is undeniable that right across the world, and therefore also in Central Europe, English is the new lingua franca that people learn in school, and that German and French follow, but very, very far behind," Mamer said.
Mamer insists that the cost of maintaining national languages within EU institutions is worth it. He says it amounts to only 2.50 euros a year -- less than a sandwich for lunch -- for each citizen of the EU.
"There would be no European Union without respect for the multilingualism of its people. You must be able to offer citizens, companies, associations the capacity to read the laws of the European Union in their own languages, or else there could be no acceptance of the European Union," Mamer said.
"You are never going to ask a Czech farmer," he says, "to have any dealings with the European institutions in anything but his own mother tongue."
In some places it seems near a glut. Briton John O'Keefe has operated a language school in Prague since the early 1990s. His "Prague Language Center" now employs 100 teachers and is one of more than 100 enterprises offering English-language instruction in Prague.
He says the expansion of the EU and globalized business has led to an explosion in demand for English instruction, but that the peak may be past.
"Yes, I think it's still growing, although it has [leveled] off from how much it has grown in the previous few years. Because, well, the people are starting to come through the state system now with a decent level of English, so they don't necessarily have much need for language instruction privately," O'Keefe said.
But other language educators say that a new demand is taking shape for a higher level of instruction. While before most students were interested in attaining conversational ability, a new generation of students wants to master the language. Many want to be able to pass standard tests certifying their ability to use English professionally.