Just announced on the Swift.org blog:
Today, we are launching the Language Workgroup , which will take on the primary responsibility of oversight of the language and standard library. With a workgroup dedicated to the language evolution, the Core Team will invest more in the overall oversight and direction of the project. The Core Team members will serve as stewards to align the efforts of the various workgroups and shepherd the strategy for building an ever more vibrant open source project and surrounding community.
For the complete details, please see the blog post.