Which framework to focus on first ... if your basics of core php are clear especially OOP concepts you can learn any framework very fast. In my programming career I have started with core php, for any new projects we (team) chooses blindly php (core). When we got a project in magento we had learned Zend and later CI and YII. My vote goes to CI and zend
I like using Slim and CodeIgniter, but if you wanna be a "hip and cool" web dev nowadays, you gotta use Laravel
If you want to learn PHP use CODEIGNITER, it is the easyst one (and less invasive) and you can learn a good concept about MVC. Then go to Laravel.
I agree with PoPSiCLe on this one. Should learn the language first. plus, I just went through this 2 minutes ago. I searched the web for frameworks and made sure to double check compatibility with my favorite hosts. What I found was people with issues. The first results were people trying to solve this problem and that problem. What I realized was this: The language in its root elements works on almost every host. The problem with frameworks is you can build a fully functional website on local host only to find it broken and giving errors once hosted. What’s the point? The PHP docs is only so big. The help and support on sites like this is huge. Why not write the extra hour or so in code just to save the headache? I don’t want to spend weeks, or a month or so with a framework just to find out my hosts version of PHP is wrong the last minute, or that I’m going to have to change 10-20 configurations... or worse... Have to search for the answer to an undocumented bug, lol.