The girl band may have been a bit of a giveaway, singing catchy pop songs in a language that was both strangely familiar and utterly alien. But among a range of romantic links, it was a meeting of a Gay and Lesbian Association that really gave the game away: Esperanto is not what it used to be.

By rights it should have died out years ago. Founded at the end of the 19th century, an international movement by the start of the 20th, and once popular enough to have been persecuted by both Hitler and Stalin, Esperanto is the international language that never quite took the world by storm.

While the rest of mankind may have forgotten about Esperanto, its adherents have proved stubbornly resistant to the suggestion that their idealistic dream of a language of peace and brotherhood — and one that is much easier to learn than English — has no place in the world today.

This week 2,000 delegates from more than 60 countries are gathered for their annual congress in the Polish town of Bialystok — a place dear to the heart of every Esperanto speaker, being the birthplace 150 years ago of the inventor of the language, Ludwig Zamenhof.

Their mission is to spread the joy of Esperanto. Such being the nature of large international movements, however, along the way there are one or two subsidiary messages that need to be promulgated as well.

Thus it is that, among the more than 200 sessions this week, there are meetings for Esperanto vegetarians, non-smokers and a group that believes that not only should we all speak Esperanto, but there should not be any nationalities either.

Possibly one of the world’s most exclusive organisations, the gay and lesbian group — samseksamuloj, literally “same-sex-love-people” — has 200 members in 40 countries, including those where homosexuality is illegal. “We have members in countries such as Cuba, China and Iran,” said Francis Soghomonian, the group’s outgoing French president. “We assure them their membership is secret. It is their only language for talking to other gay people. In Iran there is very strict censorship. They can use Esperanto as a secret language to communicate with other gays outside Iran.”

Esperanto is also popular in China, where the Government has adopted an attitude of tolerance, and in Japan, where Oomoto, an offshoot of the Shinto religion, adopted it more than 80 years ago as its way of communicating with the outside world.

The international railwaymen’s group, one of the oldest Esperanto organisations, this year celebrates its 100th anniversary. “Our purpose is to spread Esperanto among those who work on the railways,” said Istvan Gulyas, the former deputy head of the Hungarian state railway. “Railways have no borders.” There is even a specialist Esperanto dictionary of railway words and phrases. “It has more than 15,000 terms in it,” said Mr Gulyas, with evident pride.

Esperanto may be good for sidings and signal boxes, but what of love? One criticism of Esperanto is that it is not a romantic language. Not so, says Canadian lawyer Yves Bellefeuille: “I have a Flemish girlfriend and Esperanto is the only language we have in common. You can definitely be romantic in Esperanto. It has all the words you could ever need.”

Sometimes Esperanto and romance runs in the family. Helen Fantom, a retired accountant from Newbury, Berkshire, is the daughter of a mother from Essex and a father from Holland who met through Esperanto; she met her own husband at a meeting in London, and her two sons — who spoke Esperanto before they could speak English — both live with women they met through Esperanto.

Indeed, anyone visiting this week’s congress could find out rather more about Esperanto and love than they were bargaining for. In the bookstall, among the original Esperanto literature and the translations of Shakespeare, Goethe and Orwell, there was a 1970s sex manual that was significantly more explicit than anything published in Britain at the time. The Esperanto for missionary position, incidentally, is misiista pozo.

And the future? “Esperanto is a good idea waiting for its moment,” said John Wells, emeritus professor of phonetics at University College London, who is president of the Esperanto Academy. Until then, he said, they have to be patient: “The current hegemony of the English language cannot last, and the moment will come when the world sees the need for Esperanto. What we have to do is keep Esperanto in an excellent state.”

Congress chat

Kiel agrable vin vidi. Ni ne renkontis unu la alian de post Vilnius 2005, mi pensas.

How nice to see you. I don’t think we’ve seen each other since Vilnius in 2005.

Bonvolu informi viajn legantojn, ke ankau en Cilio estas esperantistoj.

Please tell your readers that we’ve even got Esperanto speakers in Chile.

Lerni esperanton estas multe pli facile ol lerni la francan au la germanan.

Esperanto is much easier to learn than French or German.

La reloj kunligas la landojn, esperanto la popolojn.

The railways bring together the countries, Esperanto the people (railwaymen’s slogan).

And literary allusions ...

Cu mi komparu vin al somertago?

Shall I compare thee to a summer’s day?

La Besto-Farmo

Animal Farm

Kvarpiedulo, jen bonulo! Dupiedulo, malbonulo!

Four legs good, two legs bad!

Alico en Mirlando

Alice in Wonderland

La Capelisto

The Mad Hatter

La Gravejo de la Fideligo

The Importance of Being Earnest

New words

Shati-bati

To happy-slap (literally, “like-hit”)

Kunsendajho

E-mail attachment (literally, “with-send-thing”)

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