> Pick one language/ecosystem and stick to it. For a given executable, you mean. One exec, one team, one language ecosystem ("C + Lua" would count as one ecos

> Pick one language/ecosystem and stick to it. For a given executable, you mean. One exec, one team, one language ecosystem ("C + Lua" would count as one ecosystem). By the time two different team work on two different executables, the boundaries you speak of are pretty clear: the two pieces of program will communicate through inter-processes means: files, pipes, sockets… At that point, you don't really care about programming language mismatch: the only common logic will be parsing and generating the common formats. If those are simple enough, you simply won't care. And if they are not, you can always use a compiler generator that outputs C code, and use that in both programs (most ecosystems have a C FFI, so that shouldn't be too hard).