The Serbian language was a language of Slavic origin used by several people during Day 1. It was the primary language of the country Serbia.
Day 1[]
Ted Cofell was originally from Serbia, and while being interrogated by Jack Bauer cursed at him in Serbian. As he was capable of recognizing the language, Jack questioned Cofell as to how he could speak Serbian.
The Drazen family was from Serbia, and they often spoke the language when talking privately. Their American contact Yelena also communicated with them in Serbian.
