[ltta]

Smalltalk is a little shrewd in some ways as outlined here. Self has already been mentioned as a great alternative (and the related papers are amazing IMO and influence most modern JITs).

But there are some other really interesting alternatives that IMO keep with the spirit: Io (io-lang.org), Ioke (defunct now, ioke-lang.org - some awesome ideas IMO) and Squeak which is being actively developed.

I'd recommend checking out some of these, I think you can easily install io via brew on Macs and used to be able to install joke as well. They improve syntax and/or add significant language features.

[staypufd]

The Java HotSpot compiler was originally worked on for Smalltalk before SUN bought the company. It along with the ideas from SELF certainly helped improve JIT systems and dynamic compilation solutions in the late 90's and all thru the early 2000's