Those who know or have heard that Zamenhof, who initiated a "universal" language" named Esperanto, also initiated a "universal" quasi-religion named Homaranismo, or a watered-down version of Judaism without practical halakha. Followers of this quasi-religion claim and seem to believe blindly that they are human beings.
I wonder how many of them are aware and whether Zamenhof himself was aware that even this identity/identification, which may impress many people who hear it for the first time, is nothing but an illusion of the ego, which is an ultimate illusion in itself.
It took me several years of studying Hasidism and other non-Jewish teachings of nonduality to realize this. The soul is our essence, and it has no identity, including the one as a human being.
Zamenhof came to this idea as one of the two possible solutions to the interethnic conflicts he had witnessed in his childhood. It may be much better than nationalism, but they are essentially the same in that they are both based on the illusion of the ego, whether individual or collective.
Zamenhof dreamed of unifying the mankind through Homaranismo as well as Esperanto, but actually, we as souls are already unified. Einstein said, "No problem can be solved from the same level of consciousness that created it." All we have to do is to change our level of consciousness. Believing blindly that our ultimate identity is as human beings only hinders this change.
Studying Hasidism and/or other teachings of nonduality is far more effective for this change. Both Homaranismo and Esperanto only keep us stuck with the same illusion of the ego, hence the same problem created by the ego they try to solve.
PS: Language is also the gatekeeper of our egoic mind, so even Esperanto can't help us transcend our ego. The true problem is not whether the language is "universal/neutral". Both Zamenhof and Esperantists totally miss this point.