> especially when you have available a rich system of code being shared in more prosaic environments I don't think this is as big an issue as you think it is.

> especially when you have available a rich system of code being shared in more prosaic environments I don't think this is as big an issue as you think it is. You can find a number of Lisp family language implementations which compile to JVM bytecode, .Net bytecode, or JavaScript – Clojure, ClojureCLR and ClojureScript are the most notable and active (even if Clojure is somewhat of an unorthodox Lisp), but there are others (such as Armed Bear Common Lisp, ABCL). So you can write your Lisp code, and easily consume those massive library ecosystems. Similarly, Smalltalk has PharoJS, and I know there have been ports of Smalltalk to JVM and .Net too (although I don't think they've been as successful). Technologies for in-process multiple language integration, such as FFI libraries, have greatly improved over the last 10–20 years. Mixing code from different languages is easier than it ever was in the past, and there are further improvements on the horizon (for example, in Java, the planned replacement of JNI with the FFM API). I think WebAssembly is really exciting – especially if they improve the WebAssembly-JavaScript integration story, which I know they are working on. Compile whatever language you like to WebAssembly, and then you have full access to the JavaScript library ecosystem; and an improved WebAssembly-JavaScript integration will likely also help simplify cross-language integration between different languages targeting WebAssembly. We have an abundant choice of technologies for inter-process/inter-machine cross-language code integration – everything from relatively modern approaches such as REST, GraphQL, gRPC, Thrift, through to more old-fashioned approaches such as SOAP, CORBA, DCOM, etc. With the rise of micro-services, server-less, etc, it is easier than it ever was to build an application containing a mix of services in different languages. Few care if your app is composed of two or three or four different containers, and even fewer care if the code in those containers is written in different languages.