A (Latin for "unknown language") was described by the 12th-century abbess Hildegard of Bingen, who apparently used it for mystical purposes. It consists of vocabulary with no known grammar; the only known text is individual words embedded in Latin. To write it, Hildegard used an alphabet of 23 letters denominated (Latin for "unknown letters").
Hildegard partially described the language in a work titled , which survived in two manuscripts, both dating to , the Wiesbaden Codex and a Berlin MS (Lat. Quart. 4ú 674), previously 9303, collected by Sir Thomas Phillipps. The text is a glossary of 1011 words in Lingua ignota, with glosses mostly in Latin, sometimes in Middle High German; the words appear to be coinages, mostly nouns with a few adjectives. Grammatically it appears to be a partial relexification of Latin, as in, a code or language formed by substituting new vocabulary into an existing grammar. Many words have ambiguous forms, such as either or meaning "dish". Likewise, occasional typos appear in the manuscript, such as glossing as attavus instead of (ancestor) or as maler instead of (mother). As a personal language, Hildegard does not describe an invented culture or history along with it.
The purpose and creation history of is unknown, and it is not known who, besides its creator, was familiar with it. In the 19th century some believed that Hildegard intended her language to be an ideal, universal language. However, in the 21st century it is assumed that Lingua ignota was devised as a secret language; like Hildegard's "unheard music", she would have attributed it to divine inspiration. To the extent that the language was constructed by Hildegard, it may be considered one of the earliest known constructed languages.
In a letter to Hildegard, her friend and provost Wolmarus, fearing that Hildegard would soon die, asks (; "where, then, the voice of the unheard melody? And the voice of the unheard language?"), suggesting that the existence of Hildegard's language was known, but there were no initiates who would have preserved its knowledge after her death.
The only extant text in the language is the following short passage:
These two sentences are written mostly in Latin with five key words in Lingua ignota; as only one of these is unambiguously found in the glossary (, "people", a likely portmanteau from German "" and ""), it is clear that the vocabulary was larger than 1011 words. ( finds probable correspondences for two other words.)
"people" is apparently inflected as a third declension Latin noun, yielding the genitive plural "of the peoples".
conjectures the translation:
Hildegard wrote the language with its own alphabet, Litterae Ignotae, which covers the same letters as the contemporary Latin alphabet rather than any peculiar sounds. The Litterae Ignotae letters also do not appear to have names of their own. Per 1100s Latin writing, the letters <Uu>, <Vv>, and <Ww> were not distinguished, nor were <Ii> and <Jj>. <Qq> has a separate letter, despite rarely appearing in Lingua Ignota words. Additionally, each word takes an initial capital, fitting the way nouns are capitalized in High German. Punctuation is seldom seen and not described.
Modern latinizations often write <Vv> and <Jj> before a vowel but <Uu> and <Ii> elsewhere. Doubled <Uu> or <Vv> is common and is frequently transliterated as <Ww>. Other writers use conventions of the time (writing <Vv> initially and <Uu> elsewhere), while some use <Ii> and <Uu> or <Vv> in all cases. The use <Vv>, <Ww>, and <Jj> before consonants is not clear, nor are sequences of <uv> as opposed to <w>.
Hildegard never described the pronunciation of the language but seemingly follows conventions of her native Middle High German, such as using the letter <Zz> much more than <Ss>. Lingua Ignota <Zz> could have represented or , or perhaps both depending on the word. <Ss> in turn likely represents something like or . Overall, however, what sounds are represented by each letter and in which word is not always clear.
Lingua Ignota uses frequent multigraphs such as <sch>, <nowiki><th>, <ph>, <sz>, <ei>, among others. It is not clear how many denoted unique sounds not covered by the standard alphabet, nor if any sounded the same as specific single letters or other multigraphs. Like the singular letters, their consistency in pronunciation is not known. </nowiki>
The glossary is in a hierarchical order (), first giving terms for God and angels, followed by terms for human beings and terms for family relationships, followed by terms for body-parts, illnesses, religious and worldly ranks, craftsworkers, days, months, clothing, household items, plants, and a few birds and insects. Terms for mammals are absent (except for the bat, , and the gryphon, , a half-mammal, both listed among the birds). Also lacking are most adjectives, numbers, and grammatical terms, as well as any verbs, adverbs, pronouns, or function words.
The first 30 entries are (after ):
Nominal composition may be observed in many words: "father" â "stepfather", "mother" â "stepmother", and "son" â "stepson". Suffixal derivation can be seen in "father" â "patriarch". As with the orthography, Middle High German influence is evident, such as the word "grandfather" begetting the word for "ancestor": â .
A few terms have more than one Lingua Ignota word assigned to them, such as and both meaning "house". Whether there is any distinction in use and what kind is not made clear.