The mystical teachings of many traditions contain words or phrases called voces mysticae which seemingly make no sense in the language of the times. To mystics and witches, they are "words of power", "spiritual language", "mystical utterances" or even the "language of the angels". To scholars, they are "gibberish".
An example of a "mystical utterance" in Judaism is the phrase kuzu bemukhsaz kuzu on the mezuzah. The Lesser Hekhalot literature and Sefer HaRazim reportedly contain many such phrases of "gibberish" as well. An example from The Craft is the phrase eko eko azarak, eko eko zomalack.
Many of the ancient voces mysticae are words borrowed from other real ancient languages. Some hide sacred keys to a mystical craftworking.