Episode 72 of "Stargate-SG1"
s04e06 Window Of Opportunity

While investigating an abandoned alien planet, an alien scientist attempts to use the technology to reunite with his dead wife. When the device malfunctions, only Jack and Teal'c are aware that everyone on Earth and on other planets connected to the Stargate are being forced to relive the same 10-hour period over and over again, and they must try to find a way out of the loop. The two learn Latin and the Ancients' language and confront the scientist, Malakai, and manage to convince him to shut it down using the knowledge they've gained.