If someone is interested in learning a new language for the hell of it, however your school days of learning that Caecilius was sitting in the garden fills you with dread, a really cool alternative is Lojban. It is a completely unambiguous language created by the Logical Language Group and has some pretty interesting elements that sit between software and non-computational linguistics.
I won't stop anyone from learning anything they find interesting, and Logban is probably easier to learn. However I wouldn't recommend in general that anyone learn a constructed language. Learn the languages that people actually speak, they are much harder to learn, but in return you can actually talk to people, which is the point of learning a language.
That is instead of two people learning some weird language why doesn't one of you learn the others and gain the whole world of people who speak that other language instead of a rare language where everyone speaks something else.
This view is a little strange in a thread where the alternative is learning Latin. With Latin, too, you typically have to go to conventions in order to encounter other speakers...
I've participated in many spoken Latin events (and loved them), but they were akin to conlang events in that every single person was a non-native speaker, and the majority were not fully fluent. Following the view which I think I took from Ghil'ad Zuckermann (I don't know whether he would phrase it this way) that revived languages like Modern Hebrew are akin to conlangs, it seems that at least the way I speak Latin is akin to the way I speak conlangs -- great reliance on explicit knowledge, little influence from my own or others' native speaker intuition.
where most Latin speakers are happy to use vocabulary from any period almost interchangeably, even though native speakers wouldn't have.
On the other hand, even if you don't get access to spoken communication with (almost) any new people (I have only once in my life spoken Latin with another person who didn't also speak English), you do get access to millennia of "Latinity" and a perspective on the origins of modern European languages (even the non-Romance ones because of pervasive borrowings).
I want to say that every language is a world and opens new horizons of thought and culture. For conlangs, those horizons may be kind of shockingly minuscule, but they're still there. Even with the intentional extreme limitations of my favorite conlang, toki pona, I've had the experience on rare occasion of feeling like something was easier or clearer for me to express in toki pona than in my native English. But yes, learning modern languages has paid much huger dividends in being able to communicate with hundreds of millions of new people and participate to some limited extent in very vibrant cultures...
Edit: in the specific case of Esperanto there's a widely-held but controversial theory that it helps prepare people for the experience of learning other languages, maybe by helping them develop some grammatical concepts or practice certain language-learning skills.
I actually find this less plausible than I used to (it seems like many of the grammatical concepts you get from Esperanto won't map that well onto other languages), but some experiments with this did show positive results.
My tiny amounts of personal Latin&Greek studies have significantly improved my intuitive understanding of romance languages and anatomy/medicine
I unfortunately can't say the same for any of the constructed languages I tinkered with - though they were fun and possibly provided different types of cognitive gains
Definitely! That's a bit different from how you previously put it above:
> Learn the languages that people actually speak, they are much harder to learn, but in return you can actually talk to people, which is the point of learning a language.
Maybe we could emend this to
"that people actually speak or have spoken ... in return you can actually experience other people's thoughts and feelings, which is the point of learning a language"
and then it would work well for widely-spoken modern and ancient languages alike?
https://en.wikipedia.org/wiki/Lojban