June 3

What Bahá’u’lláh says is that the Supreme House of Justice will appoint a committee that will study the whole matter and then either choose one of the existing languages or create a new one, to function as an international language. The Master never went beyond that, i.e. He never tried to solve the problem Himself and choose that language. He still leaves it to the Supreme House of Justice. But He says that Esperanto will spread and even went so far as to encourage all the friends who possibly can to study it. In fact the knowledge of Esperanto has proven very useful for one who tries to teach in different countries of the world. But whether Esperanto will become the international language which is to be a part of our religious and social duties to study, no one knows, and we have no evidence that the Master made any definite statement along that line. The Master has scarcely ever assumed the solution of a problem that Bahá’u’lláh has referred to the Supreme House of Justice. Esperanto may become an international language, but it depends upon the House of Justice to choose it as the international language. And no one is in a position to foretell. 

- Shoghi Effendi  (From a letter dated 30 August 1928 written on behalf of Shoghi Effendi to an individual believer; compilation: The Principles of an International Auxiliary Language’, prepared by the Research Department of the Universal House of Justice’, 2002)