What is an Auxlang? An international auxiliary language or auxlang is a form of communication between people from different countries who don’t share a common first language. There have been “lingua francas,” pidgin and creole languages going back hundreds of years in order to facilitate trade between various cultures. However, in the 18th and 19th century, philosophers and linguists began considering the idea of a constructed, universal second language: that everyone would speak their own tongue but would have something secondary to communicate with others. (This is not quite the same as a Conlang or Constructed Language which is often used for artistic and philosophical purposes, such as Na’vi from Avatar or Quenya from Lord of the Rings).
What has this to do with esoteric spirituality? Enter one Johann Martin Schleyer, a Catholic priest who lived in the recently unified southern Germany of the late 19th century. One night in the spring of 1879, Father Schleyer had a dream: God came to him and encouraged him to develop a universal human idiom in order to unite all the people of the world. Talk about spiritual inspiration! The result was Volapük (http://xn--volapk-7ya.com/ ) . After publishing some initial information in a poetry magazine then a book, Volapük clubs popped up all over Europe along with an International Academy (Kadem bevünetik volapüka). People became certified teachers and harmony reigned in Europe for the rest of all time. . .not really. Within a decade, arguments among and between Volapük clubs erupted over proposals to reform the language, to proprogate it unchanged, and to clarify propriety rights.
Volapük also fell into the linguistic and spiritual shadow of the new language in town. A Jewish opthalmologist from Bialystok, named Ludwig Zamenhof, looked around at the linguistic and religious tensions in his own community. Eastern Poland in the 18th and 19th century had moved under the control of Prussia, Napoleonic France and then Tsarist Russia; so pretty much everyone spoke German, French, Polish, Russian, Latin and Greek (if you were educated) and in Ludwig’s neighborhood, Yiddish and some Hebrew. Zamenhof theorized that if there was a common language, then everyone could communicate with each other and stop hating each other (a long historical concern for European Jewry) while moving towards world peace. Under the pen-name Doktor Esperanto, which meant Doctor Hope, he published a booklet about a Lingvo Internacia in 1887. The number of people and clubs that used the language grew rapidly ( with a very large number still around today: https://uea.org/).
But Zamenhof wasn’t done. In 1901, he began to promote a new religious faith named Hillelism; advocating a pure monotheism with no laws other than the Golden Rule but preserving Jewish customs (this was different than the Reform Judaism of the time which was highly assimilationist). After some push-back from the non-Jewish Esperantists and rejection throughout the Jewish community, he revised the spiritual philosophy by making it more generally an ethical monotheism and changing the name to Homaranismo (Humanitarianism) in 1906. However, other religious and political movements, World War I, and Zamenhof’s death in 1917 pretty much ended the spiritual movement that he was trying to nurture in the heart of the language.
There have been many other constructed Auxlang projects, some of which have been relatively successful although not to the extent of Esperanto. (My favorites are Lingua Franca Nova: https://elefen.org/ , Ido: http://ido.li/ , Occidental: https://occidental-lang.com/ & Interlingua: https://www.interlingua.com/). While many proponents of these Auxlangs have translated the Bible and other works of spirituality into these languages, the focus is more linguistic and social rather than spiritual. . .but that doesn’t mean YOU can’t learn one or all of them and promote your own spiritual understandings – it could be fun!