There's an Esperanto expression for a topic you keep banging on about - amata ĉevaleto.

Perhaps for beating a dead horse you could say rajdi jam kadukan ĉevaleton, or, changing the metaphor, frapi je la pordo de abandonita domo, or klopodi veki mortinton.

Rafahz:Hi there,

I took part at Rio+20 as UEA-representative. That link sent by burungmarah is official. I distributed it to delegates at Rio+20. We also strategically distributed the booklet "Discover Esperanto", in Portuguese and in English.
Why adopting a national language is unsustainable? First, because there is an hegemonical language, and that gives advantage to its native speakers. At Rio+20 many people was discriminated by their language skills. To take part at the headstates convention as a representative of an UN-Major Group, for example, it was necessary to be a fluent English-speaker, and as a result all representatives of MGs was native speakers or non-native speakers who lived abroad for years! A friend of mine was invited to give a speech at a side-event, and when the organizers discovered that he wasn't an English speaker they tried to cut his speech, because they were looking for an English speaker.

At Rio+20 there was a language chaos and I got shocked because of language discrimination there. Also, as an observer at a G77 meeting I remarked the difference of English level between diplomats of poorest countries and richer ones.

Also most speakers at side-events were English native speaker. They do monopolize the debate. It's hard for poor people to have access to a foreign language, and I'm talking about fluently use it, not at a pub, but at a formal high level convention.

You can learn Esperanto for free, it's 10 times easier to learn than English, it doen't privilege native speakers and so, can be considered sustainable, as you can read here.

Thanks for your insight, Rafahz.

Right now, advocates of Esperanto can be seen more or less in the same light as eco-warriors who ride on pollutant-emitting vehicles to get around and spread the word - just because cleaner alternatives aren't abundant; they have to use the lingua franca of today communicate internationally as the 'lingua franca of tomorrow' is still not in widespread use. Not hypocritical, just living in real life on one hand and holding on tightly to their ideal on the other.

But how long more until the rampant use of pollutants pushes Earth to the brink of freakish climate change? How long until the spread of English as the lingua franca reaches saturation due to a resource crunch (i.e. run out of dedicated tutors), widening social divides between those who are fluent and those who are not? I think Indonesia's issue with English underlies the aforementioned resource crunch - the world's fourth most populous country knows she can't teach every kid the language.