I think you’re getting at the usefulness of the language but I’d offer a counterpoint which is the time you’d need to invest. The FSI estimates 500 hours until Spanish proficiency and 2000 hours for mandarin. Esperanto is more like 50, and studies show faster French acquisition after first learning Esperanto than learning French the whole time.
There's one key flaw in those studies, at least in my opinion. It's that they were done among children who had no choice. I can't imagine that someone who was actually interested and motivated to learn French would get the benefit from Esperanto. I also don't think that the benefit is all that great, and would like to see the studies repeated now, 100-years later.
Anecdotally I found it helpful because it trains some sort of "meta-learning" for languages. Once you learn a new language once, the next gets a little bit easier, things are less discouraging.
If learning Esperanto really solved the same problem that learning, say, Spanish or Mandarin would solve, then you might have a point. But Mandarin has just under a billion native speakers and another 200 million second language speakers, whereas Esperanto has as few as 63k speakers combined from both categories. The combined number for Spanish is easily 500+ million.
The only compelling argument I see is the one you mentioned about using Esperanto as a quick path to, say, French. However, if we use your Spanish numbers, it'd need to reduce Spanish acquisition time from 500 hours down to at most 450 in order for it to be a net gain. Personally, as someone who's studied Spanish as a second language, I just can't imagine it would have helped me going through Esperanto first.
Again it depends what you're looking for, if you just want to talk to as many speakers as possible and don't care how long it takes, then yes, spend 5 years intensely learning Mandarin, everything else is a waste of time.
But if you want a fast path to learning a foreign language (which plugs you into a meta language learning community), then Esperanto is very interesting.
Learning Esperanto first may lead to faster proficiency in French, but it may not be good proficiency. This is because learning the words first through Esperanto would ingrain some bad habits in the learner that will be hard to eradicate after he or she moves on to French.
What I have in mind is the fact that French distinguishes between the vowels /ɔ/ and /o/, and between /ɛ/ and /e/. When learning new words, foreigners must get this distinction down right, it is key to having a decent accent in French, and in some cases avoiding misunderstandings. Yet when French roots were used in Esperanto, those vowels were leveled as just /o/ and /e/, respectively. That means that the learner does not learn the right French vowels from the start, and is likely to continue using in French the /o/ learned from Esperanto when the vowel is actually /ɔ/ etc.
In modern language teaching, it is considered vital to avoid pronunciation mistakes from the very start, because otherwise they become too firmly rooted to get rid of later.
This is a huge hypothetical scenario, I'd caution any experiment with an N=1 but this is an N=0 example.
Anecdotally I don't think my French is worse off because I learned Esperanto first, (nor any of the other languages I learned). If anything, learning more languages makes me more aware of the importance of pronunciation as a meta-learning aspect of languages.
It's not like those French roots aren't completely mangled by English learners anyways, words like "-ion" in "situation" and "conversation". But you learn just like any other learner.
How long are you planning on living? 63,000 people is chatting to one person per day for 172 years, assuming no new people learn it in that time and you never speak to the same person again.
It's a stretch to say every one of them would want to chat with you and you with them, but by the time you get to native languages with a million speakers, isn't that plenty? Is there any significant advantage in Mandarin having a billion native speakers over German having 83 million or Czech having 10 million, or generally trying to max(number_of_speakers) as a useful metric already orders of magnitude above the number you could reasonably interact with in a lifetime?
If learning Esperanto really solved the same problem that learning, say, Spanish or Mandarin would solve,
What problem are you saying that learning Mandarin solves?
I think it’s a disingenuous interpretation to think I was suggesting one could talk to every native speaker of a target language.
With Spanish, say, I gain an immediately practical language that I can use weekly if not daily right here in the US. It gives me unprecedented access to the people and culture of Mexico, Spain, and much of the entire continent of South America. I gain access to a vast body of original literature, music, and media in Spanish that isn’t just a translation but unique to the language. These are the sorts of things solved by learning a language like Spanish.
Citation needed. I have no plans to ever go to China. Mandarin has an estimated 0 utility for me. I have read more school-level German than I ever will read or speak Mandarin in my life. The number of Mandarin speakers could be 5 or 5 trillion, if they're all half a world away it doesn't affect me. Germany is close, I have been there, I might go again.
Dunbar's number is around 150, as long as the number of speakers is sufficient that there's a good chance of finding 500 to talk to in a lifetime, and 500 books or films of interest to consume in a lifetime, more than that seems no benefit. That is, 100 people is not enough - but somewhere in the region of tens or hundreds of thousands seems easily enough for a boundary.
"There are a billion people, therefore learn this language" is even less convincing as a reason to learn something; it's popular, so you should do it".
I spent five years learning German at school and got decent grades, but also got nowhere in useful skill. I spent two years learning Latin at school and got nowhere near comprehension. I spent some months learning Esperanto on and off as an adult, and have spoken to people using it, read a simple book in it, listened to podcasts in it, changed my understanding of what it means to learn a different language, understood more about grammar and made many English word-origin connections through it, and enjoyed it.
Your hating on something which doesn't affect you, then refusing to explain your position is way more of a waste of time.
You're attributing the difference in success here to Esperanto, but my guess is the key differentiator was actually how you went about studying the language and how interested and motivated you were.
I took two years of Spanish in high school and gained more or less nothing from it. I decided one day as an adult I wanted to learn Spanish, and within a few months I could hold (very basic) conversations in Spanish.
What did I do? Well, I probably did what you did with Esperanto. I started reading extensive passages in untranslated Spanish even when I didn't know the language, looking up any word or conjugation I couldn't remember. I more or less ignored grammar, except when I just couldn't figure out why something would be said one way instead of some other way. That quickly sent me down some interesting rabbit holes that even native speakers struggled to fully explain, but as a result I rapidly got to the point of being able to form reasonably complicated sentences. I started listening to stuff in Spanish. Any time I was about to ask someone a simple question in English, I'd ask myself, "so how would I ask this in Spanish instead?" I obsessed over pronunciation, and even though I'll never perfect it I'm much better than I ever was in high school.
For what it's worth, my primary tool in all of this was just LingQ.
I'm not the parent but while you are correct that it is the same, I would not overlook the order of magnitude of difference in effort required either. If you were learning Mandarin instead of Spanish for instance, the process would be the same but everything would take ~4x as long, and based on the attrition rates I've seen from English->Chinese learning, you'd be more likely to quit before being able to read a 3rd grade passage.
I guess it's more like 150 according to the studies in the second link. Anecdotally vocab acquisition is much faster in Esperanto due to the regularity and afix system, where learning a single new word root tends to give another dozen variants "for free".
By the way the second link is a critique of a single study, and it makes a pretty wild claim: "To see whether previous study of Esperanto would assist children in the subsequent learning of East-Asian languages (particularly Japanese)."
The claim that Eo helps French acquisition is much better supported from the links in the wikipedia article, considering the more similar grammars and vocabulary.
Most languages have some kind of derivational morphology that gives you variants "for free". The Wikipedia article on morphological derivation gives some examples for English: https://en.wikipedia.org/wiki/Morphological_derivation
I don't doubt that pre-existing knowledge of Esperanto helps with learning French due to the large number of cognates, but it's implausible it helps so much that you get "faster French acquisition after first learning Esperanto than learning French the whole time". Cognates would at best allow you to learn Esperanto + French in the same time it takes to learn French alone, but Esperanto isn't 100% Romance-based, so even that is unlikely.
In English getting the exceptions wrong ("I washed, I jumped, I readed, I runned, I eated, I writed") makes you sound like a child or an idiot (Ralf Wiggum from the Simpsons). In Esperanto, ending a word in "-e" makes it an adverb which means you can stick it on any root word to force adverbness. In English "-ly" makes something an adverb, except when it doesn't; "brolly" which is a noun, "fly" which is a noun, a verb, maybe an adjective, maybe sometimes an adverb ("fly-tipping"?), or "scaly" which is an adjective and doesn't become "scalyly" to make it an adverb. They aren't "for free" in English because you can't trust the pattern.
but it's implausible it helps so much that you get "faster French acquisition after first learning Esperanto than learning French the whole time"
I'm not convinced that it's true, but it surely is plausible; the other side of "can't trust the pattern" is that you can't easily see the pattern. Learning arithmetic then calculus seems better than trying to learn both at the same time; learning an instrument first then playing in an orchestra would be better than trying to join an orchestra and play with them while learning to play an instrument at all. People recommend beginners start with Python rather than 3D engine development in C++, or work on a model of an engine before they take a helicopter apart, right? Why not "learn European grammar rules in simple patterns" then "use that knowledge to climb faster through native languages which aren't so simple where the patterns are less clear"?
Esperanto has a Wikipedia of a quarter million articles, the Klingon Wikipedia was locked because there weren't enough speakers (last estimate from the 1996: 12 speakers) and the language is fixed and too limited to make for reasonable articles.
"Don't prioritize Esperanto over Klingon" is trolling.
If you're considering going to work in China, and wondering if you should learn Spanish instead of Mandarin, what are you doing. If you're trying to get a promotion in a Spanish-speaking company and considering learning Mandarin instead of Spanish, what are you doing. If you're considering learning Chinese or Spanish for utility, it seems extremely unlikely that they would lead you to exactly the same opportunies; if you can't tell which would lead to better opportunities AND you can't tell which you have more interest in, that suggests you don't have much utility for either, much interest in either, and should do something else more immediately beneficial instead. e.g. skills training for a specific promotion at your place of work, or sought after skills in your local job market.
If you're considering learning anything for fun or interest, then learn the thing which you find fun or interesting, not the thing which internet people tell you that you "should" based on something so completely irrelevant as how popular it is. Keeping up with the Jones's is a mistake, not a desirable way to live.
