Articles on the web indicate Google will make Swift work on Android. This does not mean iOS apps will just run on Android. Apple did not open source the infrastructure for iOS apps, just the programming language. The benefit of having Swift run on iOS, Mac OS, Android, Linux and Windows is now there is one cross-platform language people can agree on for writing user interfaces. Still, the backend code will have to be written in C++ if there is any chance of solid cross-platform portability for the logic that integrates with the actual platform. Swift and C++, C, solid combination anyway you slice it.