In GR8Conf EU, @kenkousen spoke about fighting reality vs perception around Groovy. Check out the third slide in this Kotlin talk:
Reasons why Groovy is not a good fit for Android development:
How about Groovy?
• Groovy is dynamic
• Harder for IDEs to parse and infer
• Won't ever be consistent with Android
Harder for IDEs to parse and infer -> Specially vs a language developed by an IDE manufacturer
Groovy is dynamic ->@CompileStatic anyone?
Won't ever be consistent with Android -> WTF?
That said. Kotlin looks good and Swift syntax resembles Kotlin's syntax a lot. That will probably help the creation of multi-platform development teams coding in Swift for iOS and Kotlin for Android.