High Gothic, also called Tech by the adepts of the Adeptus Mechanicus, is the hieratic tongue of the Imperium of Man, often used in the formal titles of ancient Imperial institutions and organisations (such as the Adeptus Terra, Adeptus Astartes, Astra Militarum).
It represents an older language than the commonly used Imperial vernacular tongue and is regarded as a sacred tongue since it was the language spoken by the Emperor of Mankind during the era of the Great Crusade in the late 30th Millennium.
At that time, the language was simply called "Imperial Terran" or "Imperial Gothic." In the current Age of the Imperium, High Gothic is the equivalent of the Church Latin used during the mediaeval age of ancient Europe.
High Gothic is also known as "Tech" because it is a version of the language in which the technical rituals of the Adeptus Mechanicus and other ancient works are recorded.
High Gothic first developed during the Dark Age of Technology on Old Earth before the spread of Mankind to its interstellar colonies. It derives from the common tongue of that time, an assimilation of English, European and Asian-Pacific languages which developed over many centuries in the North American, European and Asian-Pacific regions of Terra.
High Gothic was the universal medium of Humanity's written record in the late Age of Terra and the Age of Technology until the advent of the Age of Strife, and was spoken as a first language by many and as a second language by almost everyone.
Its idioms and vocabulary now appear archaic and mystic to the peoples of the present-day Imperium and many of its words have acquired religious significance over the years. It is the liturgical language of the tech-priests of the Adeptus Mechanicus and of forbidden books of heretical and daemonic lore.
High Gothic (represented in-universe by pseudo-Latin) is unintelligible to most Imperial citizens. It is only the language of important adepts and members of the Inquisition, and even among those who can speak it, it is only a second language.
It is used principally in formal situations (such as during pious benedictions by a priest of the Ecclesiarchy), rather than as a casual language of conversation.
Low Gothic, a bastardised, present-day version of High Gothic (represented in-universe by English), is the current common tongue of the Imperium in the late 41st Millennium.
- Warhammer 40,000: Rogue Trader (1st Edition) by Rick Priestley