From the Dylan Exchange Website:
Dylan is a general-purpose high-level programming language, designed for use both in application and systems programming. Dylan includes garbage collection, type-safety, error recovery, a module system, and programmer control over runtime extensibility of programs.DRM-TR
Dylan combines the major efficiency advantages of static languages (C/C++, Pascal) with the flexibility advantages of dynamic languages (Scheme, Smalltalk). Dylan is not proprietary; in addition to Apple's own compiler effort, there are at least 9 non-Apple implementations under way, including alternative and commercial environments for Windows and unix.Steve Strassmann, PhD email@example.com
See also Scheme-vs-Dylan.