Well, I think it is wise at this point to learn some ObjC if you're just starting out with iOS development. If you plan to interface with (and therefore potentially debug) any 3rd party code it will be pretty important to know. Also many (most) iOS examples will be written in ObjC. The bridging between Swift and ObjC will remain important for awhile I'm sure.

So, in my opinion it is words from the wise - I'd still recommended focusing on Swift for experienced developers jumping into iOS development, but understanding the ObjC underlying just about everything one will do in Swift is important.