How Can I Write a Multilingual Application?

If you're referring to multilingual output—like supporting different human languages in your app—that’s about internationalization (i18n) and localization (l10n). You have to define everything your program outputs in various languages and implement a lookup system that fetches the correct phrases based on the current language. Dates and number formats differ by region, so that’s where localization comes in. Look up i18n and l10n frameworks for your programming choice!

A practical approach is to have one program read the output of another. If you want optimal performance, you'll need to write additional code to share internal structures. Using C as a common language, you can find C bindings for various languages. This would let you write efficient libraries to use, like how numpy operates with Python.

You can link C into C++ or run Python within a C file using python.h. If you have something compiled, that binary can be executed in a C file. The key is having a solid reason to mix languages. For example, I have a C++ library that I bind to Python, which works well for my needs. Any two languages capable of reading and writing files can interact, and this principle can extend to game servers too.

If you’re thinking about using multiple programming languages, many web apps mix one for the backend, like Python or PHP, and another for the frontend, usually JavaScript. The typical method is to build your app with a backend language and serve the JavaScript files as static assets.

If you get adventurous and want to use multiple languages on the backend too, you might look into microservices, but that's a more complex setup, especially if you're just starting out.

It really depends on what you mean. Sometimes one language is fully embedded within another, like how Lua is often used. Other times, languages operate separately but communicate through a "translation layer". Some natively support each other, like Clojurescript and JavaScript. The communication method really hinges on why you’re using two languages and what they’re meant to do together.