Weil er kein Englisch sprach.
The Liber Regalis was translated into English for the first time for the coronation of James I in 1601, partly as a result of the reformation in England requiring services to be understood by the people [. …] The Latin text was resurrected for the 1714 coronation of the German-speaking George I, since it was the only common language between the king and the clergy.
en.wikipedia.org: Coronation of the British Monarch