Ronald Glossop, a retired professor of philosophy and peace studies at Southern Illinois University, walks into the Silver Bay conference center on the shores of Lake George in New York and greets his friends with, “Saluton.” One responds with “Kiel vi?” and they continue to discuss their work and hectic travel schedules.

Glossop and his friends aren’t Trekkies speaking Klingon. They’re Esperantists exchanging niceties in Esperanto, a fantasy language dreamed up by Polish ophthalmologist Ludwig Zamenhof in an effort to create a new, neutral base language for international communication.

First introduced in 1886, Zamenhof’s invented tongue currently counts around 2 million speakers worldwide, according to the UEA, the Rotterdam, Netherlands-based international Esperanto organization. And it’s growing. There’s been such a rapid expansion of Esperanto in Africa and Asia that Chinese television recently ran a course on it.

You’ve probably heard of Esperanto, perhaps as a punch line in a pub quiz or during your idealistic college years, but it’s likely been a while since someone greeted you with a Saluton. Its popularity and novelty have waxed and waned since its peak in the 1920s, when professors at Harvard and Columbia taught it as a viable language. It all but disappeared with the rise of the Second World War, but then returned with the altruism of 1960s counterculture. Esperanto has since cropped up here and there in mainstream culture; Elvis Costello used it in the liner notes for Blood & Chocolate, for example, and it was incorporated into the video for Michael Jackson’s HIStory. It was even nominated for a Nobel Peace Prize in 2008. But most of the world has never encountered the language.

Bill Harris is trying to change all that. Harris learned the language 20 years ago when he realized that French was far too complicated for a Maine husband with small children to pick up as a hobby. After finding a copy of the now out-of-print Teach Yourself Esperanto and becoming fluent in about six months, Harris had an epiphany: “This is really a peace movement,” he realized. “We Esperantists believe that in the long term we can use neutral language to contribute to peace and harmony in the world.” Zamenhof would have agreed. He concurrently created Homaranismo, a neutral theology based on “humanitarianism,” which fostered the same live-and-let-live ideals he focused on with his language. While the religion didn’t quite take hold, Esperantists tend to spread their enthusiasm with an almost evangelical fervor. And they like to be together under that big tent. When Harris retired and his wife died, he left his home state for California and the chance to help the cause he believed in. Since 2007, he has been the director of the central (and only) office of the nonprofit Esperanto-USA, in Emeryville, California.

Harris’s organization creates events and spreads the gospel of Esperanto in the States, while TEJO, the youth division of the UEA, goes after the younger set. The organization compiles an annual list of Esperantists willing to host fellow speakers in their homes for a couple of days. The list, known as the Pasporta Servo, is available online for $15.10 at Esperanto-USA.org; the website, pasportaservo.org, connects people socially and includes profiles of hosts, much like any home-swapping or cultural exchange site. Among the 1,300-plus willing hosts, you’ll find singles, families, and older couples all eager to donate their guest bedroom in exchange for some konversacio. The catch: The entire site is written in Esperanto.

Amanda Higley Schmidt was so excited about Pasporta Servo that she booked a ticket to Paris, bought a rail pass, and spent 16 months traveling around Europe. She paid for lodging only three nights during her travels, relying instead on the kindness of Esperantist strangers. “I first got interested in Esperanto in college,” says Schmidt, who lives in Sacramento, California. “I also took Hebrew, Swahili, and French, but Esperanto was exhilarating. It was so easy and logical. You mix prefixes and suffixes and make your own words.” Schmidt now speaks to her kids only in Esperanto (which sounds vaguely like Spanish); like most native-born American youth, they reply in English. “My daughter didn’t even really know she was fluent until we attended an Esperanto New Year’s Festival in Germany last year,” Schmidt says. “She tried to speak English with our hosts for three days and was so frustrated. She finally broke down and spoke to them in Esperanto.”

Truth is, Esperanto was meant to be easy. “A large majority of the core root words, about 70 percent, are based on Latin,” says Duncan Charters, a professor of language at Principia College. “The rest have German or Slavic roots.” To make matters even simpler, the vocabulary in Esperanto is regularized where it isn’t in major languages. “Bull,” “cow,” “calf,” “herd,” and “stall” all use the same basic root related to the animal, with different suffixes to distinguish specific meaning. There is a dictionary, which has the kind of authority carried by the Oxford English Dictionary, and which is ratified by the Esperanto Academy. And like English, Esperanto is a living language; the community eventually adopts whatever term has become most recognizable.

And thanks to the Internet, the language is once again gaining traction here in the States, as curious young Esperantists connect and learn online. You can now translate your Google search into Esperanto, if you so desire. You can study the entire lexicon and practice speaking it at lernu.net. For millennials, this is exhilarating, like learning a secret code. Seventeen-year-old Greg Zales became fluent in the language after studying it on lernu.net for three years. “I was looking up strange holidays and I Googled Esperanto Day,” says Zales, who lives in Darien, Connecticut. “I had no idea what it was, but once I got some information at the lernu! site, I was hooked. I read Esperanto literature, watch Esperanto movies, ‘speak’ with Esperantists in chat rooms.” Recently, Zales was named Translator of the Month on Facebook.

For those looking for a more classically conversational experience, there are monthly meetings in many urban locations—though Amanda Schmidt admits that the one she attends in Sacramento generally draws only about three attendees. Other gatherings around the world tend to attract larger crowds. The Universal Congress of Esperanto has been meeting yearly since 1905 (aside from the years of the World Wars) and gathers 2,000 speakers for eight days during the summer. Its location changes annually; the 2012 conference will be held in Hanoi, Vietnam (a burgeoning Esperantist city), and 2013’s will be held in Reykjavik, Iceland—the country with the greatest percentage of Esperanto speakers per capita in the world. But then, the entire country has a population of only 300,000.