English is a human language that developed in England. The current form of the English language is in the era known as Late Modern English, having already been through three earlier incarnations. It is part of the western branch of the Germanic language family which it is speculated the Asgard originally helped contribute towards.
After the Anglo-Saxons invaded the territory, that is now modern day England in the late 5th century, they founded several Kingdoms of their own and the original Celtic languages where slowly replaced with their Language (Old Saxon/ Old English) as these Germanic settlers soon became a majority in the southern part of Britain. Viking raids, language contact with Scandinavian settlers and Christianization contributed towards influences of Old Norse and Latin in Old English, whereas the Norman Conquest in the 11th century was mainly responsible for the transition to Middle English and the abundance of gallicisms found in Modern English. The colonial campaigns of the British Empire and the post World War II influence of US-American media, economy, science and politics helped to establish Late Modern English as a lingua franca in many aspects of human life throughout planet earth.
- The producers make almost all newly encountered people on alien planets speak English for the sake of convenient storytelling, though their writing is invariably alien. The characters on the shows seem to be generally unaware of the "miracle English" phenomenon, although it was subtly parodied in the episode "Wormhole X-Treme!" of Stargate SG-1. Stargate Universe has generally attempted to avoid the phenomenon except in cases where it's in keeping with canon (namely the Lucian Alliance), instead creating aliens with their own language or alternate means of communication.
- In a few episodes of Stargate SG-1, characters that appear to be speaking English are most likely speaking their own language, which is simply being translated for viewer convenience. Examples include the Goa'uld meeting in "Summit" and the Ancients in the beginning of Stargate: The Ark of Truth.
- In the original Stargate movie Daniel Jackson took quite some time learning the language of the Abydonians which was related to ancient Egyptian. This is in contrast to the "miracle English" phenomenon in the TV-series.