I think you're mixing concepts here. Swift is a programming language, Cocoa is the app development framework for macOS. You can already use Swift in Linux (and

I think you're mixing concepts here. Swift is a programming language, Cocoa is the app development framework for macOS. You can already use Swift in Linux (and I suppose there are already some WIP bindings to GTK). Cocoa is a totally different beast, really dependant on internal workings and semantics of macOS, and porting it would definitely take more than a single release cycle. And Kotlin does not have any association with Google whatsoever. If you want a single language / development framework for mobile and desktop, I think the best option right now would be React Native, given that Canonical created a Ubuntu Desktop fork.