Despite efforts to emphasise Esperanto's utility and downplay any ideological stance attached to it, people increasingly used the language to advance their social, political and religious viewpoints. Zamenhof himself considered the language as just a part of his efforts to bring humankind together through Homaranismo, his philosophically pure 'religion of humanity' (Couturat and Leau 1907: 40; Lins 2016: 25— 28). Although Esperantists attending the second Universal Congress of Esperanto, in Geneva, in 1906, broadly rejected the association of the language with Homaranismo, Zamenhof insisted on supporting what he called Esperantos interna ideo (inner idea). A softened form of Homaranismo, the interna ideo placed fraternity, equality and justice at the core of Esperantos raison d'etre, with the language being reaffirmed not as an end in itself, but as a means to reach fairer communication and more egalitarian human relations.
During the first half of the twentieth century, Esperanto went through a period of institutionalisation, spread and diversification, as well as opposition. Following Zamenhof's plea to give up his owner- ship of the language on behalf of its growing speech community, some institutions were established, notably the Lingva Komitato (Language Committee, aimed at stewarding the evolution of the language) and the Kongresa Komitato (Congress Committee, responsible for organising the annual Esperanto congresses). In 1906, Hippolyte Sebert founded the Esperantista Centra Oficejo (Esperantist Central Office) in Paris, bringing these two committees together under one administrative struc- ture. In 1908, Hector Hodler founded the Universala Esperanto-Asocio (Universal Esperanto Association, henceforth UEA) in Geneva. With UEA, Hodler aimed to provide services and support for Esperantists, as well as to set the grounds for the establishment of a more practical form of internationalism: Hodler's speeches and writings encouraged Esper- antists to make concrete efforts towards the improvement of human relations around them, rather than merely speaking abstractly about brotherhood among peoples (Lins 2016: 33). This combination of idealism and practice led UEA to reach 7,000 paying members in 1914. Following the death of Zamenhof, in 1917, this association came to be regarded as the new leadership for the movement.
With the outbreak of the First World War, the Universal Congresses had to be suspended for several years and, because freedom of circula- tion was compromised in many places, other Esperanto meetings became more sporadic. Against this background, UEA took advantage of the neutrality of Switzerland (where its headquarters were located—before the association moved to London and, subsequently, to Rotterdam) to help those in need by delivering food, clothing and medical supplies and by forwarding family correspondence. Anyone facing difficulties to exchange letters directly due to the blockages of correspondence coming from hostile countries could send their letters to UEA. The association would then forward these letters to the addressee, as well as provide trans- lation from one language to another if needed (Forster 1982: 159; Lins 2016: 49). This service was widely announced in the non-Esperantist media, spreading the word about Esperanto while helping people who otherwise would be unable to communicate.
The First World War brought about further changes: the linear percep- tion of progress and modernity largely held during La Belle Epoque and epitomised by the Universal Exhibitions collapsed. Relatedly, the universalist rationale underpinning Europe's perception of progress lost momentum. These changing circumstances were followed by the estab- lishment of significant links between Esperanto and political stances. Closely bound to the war, there was an increase in the use of Esperanto by the working classes, anarchists, communists and pacifists—in sum, by those who were against both the war and the nationalist issues that prompted it. To gather the rising number of left-wing Esperan- tists, Eugene Lanti[8] founded, in 1921, the Sennacieca Asocio Tutmonda (World Non-National Esperanto Association, hereafter SAT), headquar- tered in Leipzig and, later, in Paris. Lanti also launched his manifesto For la Neŭtralismon! (Down with Neutralism!) (Lanti 1922) as a response to UEA's neutrality. He identified the broader Esperanto movement as bourgeois and argued for an international forum in which like-minded proletarians and laypeople could regard Esperanto not as a cause to be advanced in its own right, but as a tool for people to communicate their political convictions, exchange ideas and hold debates. In this sense, the creation of SAT reinforced a partition between the hitherto neutral Esperanto movement and the emerging left-wing, workers' Esperanto movement, leading to a schism along class lines (Markov 1999; Lins 2016: 64).
The politically engaged, internationalist use of Esperanto during the period of the World Wars partly hindered the expansion of the language. In interwar Germany, a nationalist wave arose among Esperantists, with some using the language to promote German nationalist values beyond German borders. At the same time, still in Germany, the Nazi regime started to regard the internationalist and pacifist values often associ- ated with Esperanto as a threat to National Socialism and patriotism.[9]The hostility against Esperanto—which had started with attempts to suppress the left-wing, workers' Esperanto movement and the political activities of some Esperantists—soon affected also the neutral Esperanto movement as the language became increasingly associated with anti- fascists and revolutionaries and considered as a means for spreading 'dangerous' ideas.[10] The Third Reich monitored Esperantists closely and shut down numerous Esperanto associations and clubs. Meanwhile, in 1925 Estonia, a number of workers' Esperanto groups were prevented from beginning their operations due to the incarceration of most of their members, and people in Bulgaria, Romania, Hungary, Italy, Lithuania, Latvia and Poland were forbidden to receive publications from SAT (Lins 2016: Part II). Primarily a persecution of left-leaning Esperantists, the situation developed into general hostility against Esperanto's very right to exist.
In the meantime, in Esperanto's cradle, the language was faring any better. Following the 1917 Revolution, the language became conveyed in Eastern Europe as a tool to bring the worldwide proletariat together, helping in the creation of a proletarian international culture. However, the late Lenin government interrupted the support that Esperanto had begun to receive by placing a stronger emphasis on proletarians being brought together on political and economic grounds. Lenin backed local ethnic, cultural and linguistic diversity and fought illiteracy in the Soviet Union, but the creation of an international proletarian culture through an international language was not among his administration's priorities. Later, the Stalin government directed the Soviet Union to a Western-driven model of nation-state. This was pursued through efforts to consolidate Russian as the national language, which marginalised not only Esperanto, but also minority languages spoken in Soviet territory
(Lins 2016, 2017).
While Esperanto faced political hostility, a major opportunity for its official recognition by an international body appeared with the creation of the League of Nations in 1920 and its replacement with the United Nations in 1945. Acting as an international pressure group, UEA circu- lated a petition urging the UN to endorse and encourage the spread and use of Esperanto. During the 1954 UNESCO General Conference, Ivo Lapenna (then president of UEA) presented a detailed report, alongside the petition, stating the commonalities between this association's efforts and UNESCO's mission. In response, UNESCO put forward a resolu- tion in favour of Esperanto, awarding UEA the status of an organisation in consultative relations with the UN and UNESCO (Forster 1982: 242—248). This status was significant in shaping the new directions followed by UEA, with human rights becoming one of the key features in the associations agenda. In doing so, UEA redefined its conception of neutrality: in trying to distance itself from an image of passivity, the promotion of Esperanto would become closely linked to the defence of human rights, especially in its linguistic aspects, through language rights and the defence of minority languages.