English

English is a West Germanic language originating in England and the first language for most people in Australia, Canada, Ireland, New Zealand, the United Kingdom, and the United States of America—together, commonly known as the Anglosphere. This language has grown to prominence as the dominant language of the Unified Earth Government and the human species, and is the primary language of every known human colony and organization.

Several other languages are used throughout human space, mostly with secondary roles in society, as English is always found in conjuncture with them. Such languages include Swahili, Hungarian, and Spanish.

Covenant translation software intercepted human COM transmissions after the First Battle of Harvest, and thus the Covenant learned English quickly. Following first contact at Harvest, the High Prophet of Tolerance had five hundred teams of well-educated Sangheili and Unggoy formed to study and translate English. These teams could only speak English among themselves and were later required to teach it to all Covenant military units. From 2525 to 2552, the Covenant used this knowledge mainly to broadcast florid curses at human colonies and ships before destroying them, and never actually held conversation with humans. Several other species had the ability to speak English, including the San'Shyuum and Unggoy, a fact the latter take great pride in. Kig-Yar could speak English in a rasped manner, though most are unable to form a proper "f" sound in speech. Most Sangheili could speak English, although they had difficulty pronouncing words containing the letter "v" or ending with "p".

UNSC translation software has been able to decrypt a number of Covenant languages, most notably those of the Unggoy, Kig-Yar, Sangheili, and San'Shyuum. By the time of the Battle of Earth, this software could automatically interpret anything that most of the races said, and has apparently been installed in the equipment of all UNSC military personnel, as all personnel appear to have the ability to understand what members of these races are saying. However, by 2552, the Yanme'e language was still largely untranslated.

Trivia
Grunts, Elites, Brutes, and Prophets can be heard speaking English in Halo 2, Halo 3, and Halo 3: ODST due to UNSC translation software.