A common question I get is, I’m new and learning iOS development. Should I learn Swift or Objective-C?. Here is a summary of what I tell them.
Learn Swift. Over the summer it was in beta, but its now pretty stable, and there are already tons of tutorials available. Swift can import in Objective-C libraries, and the Cocoa Touch frameworks, and other 3rd party code.
At the same, you definitely should at least get familiar with Objective C syntax, as many existing libraries and tutorials are written in Objective C - this makes figuring things out or making a quick edit relatively simple.
I switched over from Objective C to Swift for all of my new projects, and haven’t missed Objective C at all. Swift is fun to use, and much easier to work with than Objective C. I love it, and do not plan to go back, unless absolutely required.