Thank you for the link.

I challenge the accuracy of the statement

"Time needed to reach a standard equivalent to A-level[4]"

1500 hours for a French speaker

150 hours for a French speaker"

found there.

I think this correctly represents what Esperantists believe about Esperanto--that it is "ten times easier" to learn than some important natural language the Esperanto-learner might otherwise have occasion to learn. But I doubt the accuracy of these figures, because I think that the comparable level of language proficiency across different languages is not rigorously defined, and in all cases there are weaknesses in study design

http://norvig.com/experiment-design.html

that don't led confidence to the conclusion that Esperanto is an order of magnitude easier to learn than some other language of interest. I have never seen a conclusion like this verified in

a) a major, peer-reviewed journal of linguistics or language teaching of any kind,

nor in

b) a governmental program for training and testing professional polyglots, such as translators or interpreters.

But even if I accept that statement as true (which I do not), then Esperanto still has a problem. The highest CREDIBLE estimate of the number of Esperanto speakers I have seen is 3 million, some large percentage of whom live in Europe and already speak English or French (or both). A French speaker who learns English enters a speech community with no fewer than 300 million speakers (TWO orders of magnitude more than Esperanto, by anyone's count) and perhaps as many as 1 billion speakers. (Any count of language speakers at a given level of proficiency that finds 3 million Esperanto speakers would find 1 billion English speakers, I am sure.) So the learner, for the learner's time, money, and effort, gets at least TEN TIMES the return on investment of new people to talk to for investment in learning a language from English as from Esperanto. (Similar reasoning would explain why monolingual native speakers of English would rather learn Chinese, Spanish, French, German, Japanese, Arabic, or many other languages rather than Esperanto, which is the observed reality of the behavior of language learners.)

Let me explain from what point of view I comment about Esperanto here. If someone who likes Esperanto says, "I have enjoyed studying Esperanto and reading Esperanto publications," I would say, "I have too." When someone tells me about a hobby, for example by saying, "I really like to collect postage stamps," I say, "That sounds really interesting" and congratulate the person on finding an interesting hobby. I might mention one of my hobbies (one of which is learning new languages) in reply to that. I would never say anything bad about someone's hobby in casual conversation, whether than hobby is horseback riding, or oil painting, or composing music, or sky-diving, or rock-climbing, or playing the tuba, or whatever.

But if someone says to me, "I have a serious proposal for solving a world problem," I will ask questions about the proposal. First of all, I will ask basis of knowledge questions to see if the person has some reason for thinking that the proposal will really help with the problem. I might ask follow-up questions to find out which people advocate for that proposal and what interest they may have in the proposal being adopted. I would definitely ask about policy trade-offs such as costs and benefits. I would expect a person who is proposing to solve a problem to have a lot of thoroughly gathered and carefully considered information about different solutions and which solution might be most fitting. I wouldn't rely on just one partisan advocate to convince me what proposal makes the most sense, but would consider many sources of information. If Esperanto is proposed as a way to get people talking to one another who don't share a native language, I want to know a lot of details about how well that has worked in previous attempts.