Smalltalk [L1 ] is a pure object environment and programming language. Read the link to learn more.
Smalltalk is the oldest mature pure object-oriented language. It is genial, simple, and has only a few keywords. It is similar to Tcl in that the control structures are not part of language.
Almost all good things known in new hype-languages come from Smalltalk. That is
Also many popular program-techniques were developed under Smalltalk first. That is Extreme Programming (with Unit-tests), Refactoring Tools, Visual Programing, MVC (Model View Controler).
Smalltalk has also good designed standard libraries (Collections, Process Controll, IO).
Why is not Smalltalk the first most popular object-oriented program language? The reasons could be:
XOTcl is object-oriented extension for Tcl that has some characteristics from Smalltalk. It is also dynamic and has metaclasses and also have the same feeling.