I don't see a problem. Sockets provide a way to communicate, sockets nowadays are used almost everywhere. They have their limitations but its a viable , very fast and simple solution.
I vaguely remember that Squeak had the Ometa project that was working as a converter between languages , I think Java was supported.
Keep in mind that supporting syntax is one thing, semantics is the other� Ometa is just a (very nice) tool for making implementing a parser for syntax easier, very much like PetitParser.
I once did a very, very naive demo of adding other *syntax* to Squeak�
But the problem is that the *semantics* are still that of Smalltalk, and it�s completely not clear for the programmer where the similarity ends.
If you want to have �I can type in examples from my ruby book� compatibility, you need to implement the real semantics, which in many cases
means to re-implement the VM of that other language (in a very slow version) on top of your VM which does not really have the properties to
support those semantics.
There has been more research recently about multi-language VMs� or frameworks to build VMs (PyPy, for example). Without this support, getting 100% correct
semantic *and* be fast enough (not even fast) is very hard.
Marcus