Tbh, I have never heard of Pike or societyserver before, will check those out!
As for smalltalk, I am also not intimately familiar with the language, but what I have in mind is somewhat lower level, with emphasis on C-like struct layouts stored in a POD way (so raw structs inside arrays and the like).
I'd say a key difference is in my language (working name Dream (because I started the project as my 'dream' language, and picking names is hard)), is that these isolation contexts are explicit, and you pointers can't really cross them.
There are special 'far' pointers that do have the ability to reference external objects in different context, but there's an explicit unwrap operation that needs to happen that can fail, as that object is not guaranteed to be reachable for whatever reason. Processes can be explicitly deleted, meaning all reference operations to them will fail.
To be clear, when i say process, i mean my lightweight internal isolation thing.
So in summary, my langage is procedural inside processes, with in-process garbage-collection, C-like performance and explicit method calls. Between processes, you either have smalltalk-like signals, or you can do Rust-style borrows, where you can access objects inside the process for the duration of a method call.
It has erlang-like 'just let it crash' philosophy, but again is a C-like procedural language (or shall I say Go-like, since it has total memory safety and GC).
It also has familiar C-like syntax, and quite a small(ish) feature set outside of the core stuff.
I have a huge doc written up on it, no idea if it would work and if it did, it would be useful, but I do have some tentative confidence in it.
(Also no claims on being original or inventive.)