Different applications written with different programming languages should be able to function within a single module. Essentially, a microservices-packed module should be able to be used to deploy multiple services across multiple disparate environments and offer application updates without reconfiguring the endpoints.
Presently, https://www.fermyon.com/spin can run applications in any language that compiles to WebAssembly with WASI support.
To ensure different programming languages can work together within WebAssembly modules, they all need to create a translation layer.
The recently released roadmap for WebAssembly by the WebAssembly Community Group (CG) and the WASI Subgroup within the W3C for WebAssembly Core, WebAssembly Component Model, WASI and other WASI-based interfaces did cover language support.