As regard the chanting of Tablets in the Temple, Shoghi Effendi wishes in this connection to urge the friends to avoid all forms of rigidity and uniformity in matters of worship. There is no objection to the recital or chanting of prayers in the Oriental language, but there is also no obligation whatsoever of adopting such a form of prayer at any devotional service in the auditorium of the Temple. It should neither be required nor prohibited. The important thing that should always be borne in mind is that with the exception of certain specific obligatory prayers, Bahá’u’lláh has given us no strict or special rulings in matters of worship, whether in the Temple or elsewhere. Prayer is essentially a communion between man and God, and as such transcends all ritualistic forms and formulae.
— Shoghi Effendi, Directives from the Guardian, p. 78