[NigelTufnel]

A slightly paradoxical advice: learn Objective-C. Learning of one thing never stops.

Suppose you're now top 5% iOS developer. 5 years later you'll probably be top 1%. That's cool.

I can see only one hugely improbable risk in doing this. If Apple goes down then Objective-C developers will be as valuable as toilet paper.

[collyw]

Come on, sticking with only one language is never a good idea. Exposing yourself to different paradigms and ways of doing things is almost certain to broaden the way you are able to approach problems in the future.