I’m soooooooo dying to do a mobile app! So for me I have whittled my next language down to either Dart/Flutter or Swift.
I am 99.9999999% sure it will be Swift 
It’s just that tiny bit of doubt of being able to make an Android as well as Swift app with little additional effort that is niggling!
The reason I am drawn to Swift is:
- It’s from Apple
- It’s fairly new, and IIRC, was influenced a little bit by Ruby (amongst other languages)
- If you want your app to stand a chance of being featured (who doesn’t?) then I would guess one made in Swift would stand out more to the editors than one made in Flutter or something else (tho I guess whichever app has the potential to make them more money would take precedence even above that)
- You can use Swift on the backend, and is it only a matter of time before Apple re-enters the server space? With specialised hardware?
If anyone else wants to learn Swift… shall we start a study group? I’m definitely up for it!!!