It is easy for me to find mentions of studies that have shown Esperanto helps with learning subsequent languages (Italian, French, etc.). But, I have never seen a mention of a study that evaluated whether learning Esperanto helped to subsequently learn English. Do such studies exist?

The reason I ask....

If there were many foreign countries that encouraged Esperanto as the first foreign language to children under the age of 10 and encouraged the learning of English when the child went on to the next stage of their schooling, then the case for teaching Esperanto to native English speakers would be much easier.

My dream is that this two way reason could grow a generation of children with both an early success with a non-native language and a basic knowledge of Esperanto. The biggest barrier that I face when encouraging the adoption of Esperanto is "How many people speak it?".

Unfortunately, I imagine the barrier to non-English speaking governments is that parents will only see that their child is not learning a useful language and that they would rather have their child learning a widely spoken language such as English, Spanish or Chinese.

I don't believe that grand ideas such as the EU adopting Esperanto will succeed until there is a much larger pool of Esperanto speakers to provide translators, teachers, etc.

It would surprise me to learn that such studies haven't been done, though I could well imagine the facilitative effect with English (as a second language) is smaller than with French.

Is there not a WIKI article on propedeŭtiko?

Here we go Propaedeutic value of Esperanto

In fact, who can count the number of speakers of Esperanto in the world ? Many people are using the bias data from wikipedia unfortunately it was not correct.

The Duchtesh Welle, German Radio said that the internet give the wing of Esperanto to soar higher. It is true. As lernu is one of the example, as long as there is an internet connection, there would be someone learning the Esperanto. Esperanto is the borderless language and internet is also a borderless medium, even China banned many websites but but not lernu.

Here is a list of words compiled by the MESG. Hope it helps you in your way to promote Esperanto.

If this research is considered as research, that propaedeutic was done decades ago in another name.

I guess what is generally reported is biased towards learning the other romantic languages, but I would imagine that English would benefit significantly. sudanglo's link showed a study that had a 40% improvement in learning English, so that is definitely not insignificant.

From my personal experience going the other way, I think that the cognates alone are a good chunk of the benefit. There are so many words that are cognates with English, and there are even more cognates with Spanish and other Latin-based languages. This greatly improves your listening/reading vocabulary when going from one language to the other. Grammar-wise I'm not sure how much the benefit would be, but learning any foreign language helps you gain a better insight into grammar in general.

I've never thought about promoting Esperanto in this way before, though. It does make more sense to market Esperanto to non-English people, since they already have to learn a foreign language to compete (Us Englishers don't need no foreign languages ). I'd bet this will always be a hard sell, since the notion of "starting early" is so ingrained in us that we don't even think that it might not be the fastest way to learn something.

grebel:I don't believe that grand ideas such as the EU adopting Esperanto will succeed until there is a much larger pool of Esperanto speakers to provide translators, teachers, etc.

Only nations have power to realize that because they are based on taxpayer's monetary input which can be financal base for (bridge) language education.

Molee page 34: '... Yet I believe such proposed languages as Volapük, Interpretor, Pasilingua, Lingua Spelin, Anglo-Franca, Lingvo Internacia, Cosmos and Clarison are great artistic helps to future race unifications. On such a race union tongue, when made a national and living family language must rest, the only true and durable basis for the much-desired 'International language' -- national before international...'

A lot of the studies were done a long time ago and by english speaking researchers wanting to look at english speakers learning other languages.

There is a lot to be done here still. In general:
those with the most difficulty learning to speak another language seem to get the most benefit from learning esperanto first. It is also not clear just how much esperanto someone needs to learn to get optimal benefit for learning another target language.

https://en.m.wiktionary.org/wiki/Appendix:English–Esperanto_relations

has a list of some words similar in english and esperanto.

I think for most people, much of the benefit in learning a target language is learned pretty early in the process and through learn cognates.

Multaj studoj estis faritaj antaŭ longa tempo kaj de anglaj parolantaj esploristoj, kiuj volas rigardi anglan parolantojn lernanta aliajn lingvojn.
Estas multe por fari ĉi tie ankoraŭ. Ĝenerale:
tiuj, kiuj havas la plej malfacilaĵon lerni paroli alian lingvon, ŝajnas havi la plej profiton de lerni la unuan lingvon. Ĝi ankaŭ ne klaras nur kiom multe da esperantoj iu bezonas lerni por ricevi optimuman profiton por lerni alian cellingvon.

havas liston de iuj similaj vortoj en la angla kaj esperanto.
Mi pensas por plejparto de homoj, multe de la profito lerni cellingvon estas tre frua en la procezo kaj per lernado.