[jorgemf]

> "Google officially supports Kotlin on Android,"

It is JetBrains who support it, Google is only going to collaborate with them to help them out and keep the support up to date.

You don't have any idea about kotlin, the API is exactly the same. It is the Java API for both Java and Kotlin. The support is more related with the tooling, no with the API.

Go, Haskell and C are completely different things. Java and Kotlin compile to bytecode and the JVM runs the bytecode. Both uses the same API in the same language (the bytecode). You only have to guarantee they target the same bytecode version, which is something Google cannot do anything about, it is JetBrains who decide. This is not like Java and C in Android. C has its own API which calls the Java API. Kotlin uses the Java API, and the JVM in the Android device doesn't know if the app was written in Kotlin or Java.

P.S. Actually Android doesn't use the compiled bytecode directly as it make some modifications, but the idea still applies.