An interesting thought experiment. Ignoring for the fact that it won't/can't happen ... I've been in groups where most people spoke several languages sufficie

An interesting thought experiment. Ignoring for the fact that it won't/can't happen ... I've been in groups where most people spoke several languages sufficiently fluently not to care (and in some cases not to know!) which they were speaking. Every time this has happened the language in use changed according to the topic being discussed, sometimes in mid-word. Sometimes one language just makes it easier to talk about something than another. In one book I have read it says something along the lines of: One speaks of love and such trivia in French, of food in Italian, of tragedy in Russian, does business in German, and addresses the servants in English. Although the book itself is a parody, the passage rings true (although perhaps not in specifics). Similarly, I regularly program in AWK, Python, C, C++, and ARM assembler, and I dabble in Lisp, Lua, OCaml and Haskell. In each case I reach for my most comfortable tool for what I'm working on, and it's not always the same one. So I think if everyone were equally fluent in every language, there would be a pidgin arise, a language that is a mixture of the others, possibly with sub-languages for specific subjects.