In the fictional universe of the franchise, the people of Earth have encountered numerous extraterrestrial races on their travels through the Stargate. In addition to a diversity of alien life, there is also an abundance of other humans, scattered across the cosmos by advanced aliens in the distant past. Some of the most significant species in "Stargate SG-1" are the Goa'uld, the Asgard, and the Replicators. "Stargate Atlantis", set in the Pegasus galaxy, introduced the Wraith and the Asurans. One of the most influential species in "Stargate", the Ancients, have moved on to a higher plane of existence. For practical reasons of television productions, almost all of the alien and human cultures in the Stargate's fictional universe speak native English. Because of the time constraints of an hour-long episode, it would become a major hindrance to the story each week if the team had to spend a sizeable part of each episode learning to communicate with a new species.