Web-based software, including both Web services and traditional HTML applications, relies on language tags to identify user's language and locale preferences. In order for an application to get the right content and present it in the right format, these language tags must provide comprehensive coverage, interoperability, and some sort of standardized meaning. There are a number of interesting developments in the area of language tag standardization and locale negotiation. This presentation examines RFC 3066 (the current standard), a new proposal for changes to the RFC (of which the presenters are the authors), and W3C efforts to link these tags to locale negotiation.