The first language I learnt  was PHP, but I have more recently picked up Python. As these are all 'high-level' languages, I have found them a bit difficult to pick up. I also tried to learn Objective-C but I gave up.
So, what language should I learn to bridge between Python to C
Java might actually be a good option here, believe it or not.  It is strongly based on C/C++, so if you can get the syntax and the strong typing, picking up C might be easier.  The benefit is you can learn the lower level syntax without having to learn pointers (since memory is managed for you just like in Python and PHP).  You will, however, learn a similar concept... references (or objects in general).
Also, it is strongly Object Oriented, so it may be difficult to pick up on that if you haven't dealt with OOP yet....  you might be better off just digging in with C like others suggested, but it is an option.
What language should I learn as a bridge to C (and derivatives)