Translation software

Translation software is computer software designed to help translate information from a foreign language into the native language of the person viewing or hearing the information.

Covenant
Despite having their own native languages, the races of the Covenant appear to use the Sangheili language as a lingua franca for interspecies interaction. However, some races, such as the Huragok and Yanme'e, have difficulty speaking another languages. To better interact with the Yanme'e, signal units contain translation software which translate another language into the Yanme'e language. While Huragok usually communicate with other races by a sign language, Covenant ships also possess extensive lexicons which can give Huragok orders. On the other hand, upon extended contact with humans following the Human-Covenant War, the Huragok were easily able to devise speech synthesizers in data pads, enabling them to communicate with comparative efficiency using the humans' spoken language.

Forerunner
The Forerunners possessed extremely robust translation software in their computers. When John-117 accessed the terminals on the Ark, the computer used words and measurements native to humanity for approximate translations. As more Forerunner records were discovered and translated by the UNSC's AI translator systems, the terms used by the terminals' translation software were maintained.

The San 'Shyuum managed to access a number of files within the Forerunner Dreadnought thanks to those systems, but they misinterpreted a number of glyphs, coming to believe that the Halo Array was used to "transcend life", instead of wipe out life.

UNSC
Early into the war with the Covenant, the United Nations Space Command developed software to help translate the languages the alien races of the Covenant spoke, such as the TSV-442, which assisted in early interrogations of Covenant prisoners. However, while the UNSC was able to make a literal translation for Covenant words, the true meaning behind them could often be extremely disjointed. This was solved when the AI Cortana managed to access a Covenant lexicon aboard the Ascendant Justice, making a more accurate English-Covenant lexicon. It would seem that it was around this time that the Sangheili language was deciphered, as translation software in the weeks preceding and succeeding the events of Operation: FIRST STRIKE was heavily updated.

The UNSC also uses a form of advanced AI translator in xenoarchaeological studies of Forerunner records, such as the Bornstellar Relation. This software, much like that in the Forerunners' own terminals, translates titles and otherwise meaningful names of individuals to their English equivalents; for example, "the Didact" or "Mendicant Bias" are used, as opposed to rendering the titles in the original Forerunner language. Similarly, the translator substitutes many of the original proper names and terms with analogous words familiar to the viewer, derived from the history, culture and mythology of the modern human civilization. This explains several proper names which appear to be out of place in their Forerunner context, such as "Promethean", "Maginot Line" or "wisdom of Harbou".