May 8

I truly deplore the unfortunate distortions that have resulted in days past from the incapacity of the interpreter to grasp the meaning of ‘Abdu'l-Bahá, and from his incompetence to render adequately such truths as have been revealed to him by the Master's statements. Much of the confusion that has obscured the understanding of the believers should be attributed to this double error involved in the inexact rendering of an only partially understood statement. Not infrequently has the interpreter even failed to convey the exact purport of the inquirer's specific questions, and, by his deficiency of understanding and expression in conveying the answer of `Abdu'l-Bahá, has been responsible for reports wholly at variance with the true spirit and purpose of the Cause. It was chiefly in view of the misleading nature of the reports of the informal conversations of `Abdu'l-Bahá with visiting pilgrims, that I have insistently urged the believers of the West to regard such statements as merely personal impressions of the sayings of their Master, and to quote and consider as authentic only such translations as are based upon the authenticated text of His recorded utterances in the original tongue. 
(Shoghi Effendi, letter of 27 February 1929 addressed to the National Spiritual Assembly of the Bahá'ís of the United States and Canada; ‘The World Order of Bahá'u'lláh: Selected Letters’; also included in a memorandum from the Research Department of the Universal House of Justice dated 6 November, 1990)