The IETF Language Tag is a standardized way to identify languages in a format that is easy for computers to understand. It is based on the BCP 47 specification, which combines language codes from the ISO 639 standard with optional subtags for dialects, regions, and other variations. For example, "en-US" represents American English, while "fr-CA" stands for Canadian French. These tags are widely used in web development, software localization, and digital content to ensure that users receive information in their preferred language. By using IETF Language Tags, developers can create more accessible and user-friendly experiences across different languages and cultures.