"E.L.F." stands for "Elf Language Formulator". It is a software program designed to facilitate communication between elves and humans. It was developed by the North Pole Workshop as a way to bridge the language gap between elves and humans. The software can analyze human speech and convert it into elf language, making it easier for elves to understand humans and vice versa. It also includes a feature that allows elves to communicate directly with the software, enabling them to give voice commands and receive responses in elf language.