Hildegard of Bingen (1098-1179), an abbess of Rupertsberg near Bingen in the 12th century, invented a language she called Lingua Ignota, which is Latin for "unknown language", and an alphabet called Litterae Ignotae, "unknown letters". She claimed the language was a result of "divine revelation".
Lingua Ignota was the first known constructed language, and is thought to have been used as a secret language. Hildegard, who wrote medical and philosophical texts and also composed music, wrote a number of songs with lyrics partly in Lingua Ignota.
The language was partially described in the work Lingua Ignota per simplicem hominem Hildegardem prolata, which was written in about 1200. The text is a list of 1011 Lingua Ignota words - mostly nouns and a few adjectives, with glosses in Latin, and some in German.
O orzchis Ecclesia, armis divinis praecincta, et hyacinto ornata, tu es caldemia stigmatum loifolum et urbs scienciarum. O, o tu es etiam crizanta in alto sono, et es chorzta gemma.
This text is mostly in Latin. Words in Lingua Ignota are in italics
O measureless Church, girded with divine arms and adorned with jacinth, you are the fragrance of the wounds of nations and the city of sciences. O, o, and you are anointed amid noble sound, and you are a sparkling gem.
Information about Lingua Ignota
Digital version of the Wiesbaden Codex, which contains the collected works of Hildegard of Bingen