Dart is an upcoming language from Google, destined to become the de-facto standard for scripting on the web. Conceptually it is a replacement for JavaScript.
Dart is a dynamic language with an optional type-system. Dart is therefore similar to StrongTalk1).
Dart will be created by a team headed by Lars Bak, who was responsible for Google's V8 JavaScript-Engine2), but more importantly, he worked to create the Self-Language3), at Longview he helped to create StrongTalk and he was responsible for the HotSpot-VM at Sun.
Also on the Team is Gilad Bracha who has a history with Lars Bak by working with him on Self, Strongtalk and HotSpot. Recently he created the Newspeak Programming language, itself a successor to Smalltalk, that he aimed to evolve by becoming smaller 4)
This suggest, that Dart could be a successor to JavaScript and Smalltalk5) alike.
1)
A very fast and optionally-typed Version of Smalltalk, that pioneered Hot-Spot compiling
2)
The V8 assembler is based on the Strongtalk assembler
3)
a fast and prototype-based successor to Smalltalk, that run nearly half as fast as C
4)
something it shares with the spoken-language newspeak in Orwell’s 1984
5)
Smalltalk is a foundational programming language that is based on pervasive message passing, pervasive dynamic strong typing, pervasive reflection and pervasive object orientation.