Ancient language

Ancient is the name given to the language spoken and written by the Alterans and their descendants, the Ancients and the Ori. The language is fairly similar to Latin spoken on Earth. Unlike in English and Latin, there are not separate letters for 'F' and 'U'; both are represented by the same symbol.

In Atlantis, the letters and numbers of the language appears both uppright and uppside down and variating in direction.

Speakers
Several people at Stargate Command were successful in understanding written and spoken Ancient. Daniel Jackson was the one who unlocked the mysteries of the language, so that more could learn it, and gained an innate understanding after his ascension and subsequent descension. Other people who are fluent in the language or at least understand it at a reasonable level are Jonas Quinn, Rodney McKay, Elizabeth Weir, Samantha Carter, Nicholas Rush, Eli Wallace, Adam Brody, Dale Volker, Lisa Park, Amanda Perry, Lindsay and numerous others.

Also, at two occasions, Jack O'Neill was able to speak it, after having the entire knowledge base of the Ancients downloaded into his mind through the repository of knowledge; each time, the Asgard erased it to save his life. Jack O'Neill and Teal'c may understand some Ancient as they were forced to learn and memorize it when they were stuck in an 8-hour time loop for several months.

To protect his computer systems, Anubis used elaborate ciphers coded in the oldest known Ancient dialect. Despite the Goa'uld's long known history of acquiring Ancient relics, the Tok'ra were unable to translate them.

Some of the Athosians have displayed knowledge of Ancient, and some give prayers in Ancient.

The Wraith language is derived from Ancient.

Words upside down can have different meanings. Letters that can be turned into another while upside down are J and R.