Real world article
(written from a production point of view)
Langford was an individual that lived in the mirror universe during the 23rd century who once had a brutal encounter with Uhura.
After the prime universe Uhura rebuffed the advances of Hikaru Sulu by displaying her ceremonial knife towards him, Sulu returned to his station. In the deleted scene, Sulu was reminded by Pavel Chekov, "Have to watch that one. She knows how to use that knife. Remember what she did to Langford?" Sulu scowled, and told Chekov to "mind your own business, Ensign," just before Kirk entered the bridge. (TOS: "Mirror, Mirror")