I don't know about Apple, but Google doesn't force you to use a specific language, they just only support a handful. And at some level your language has to be a

I don't know about Apple, but Google doesn't force you to use a specific language, they just only support a handful. And at some level your language has to be able to interop with the OS. Even before Google announced Kotlin, people were already using it or Scala to build apps. React Native is another example of an unsanctioned effort to write apps in JavaScript. So I don't think your premise is true: neither Apple nor Google impose a language, they just only support a small set of languages officially.