So I spent a lot of time trying to fugure out what Cython and Jython are and I'm still (more) confused as anyone who just started computer programming. I heard that Cython is an extension, but..is also and indepent language??
What I think I've understood is that:

Cython/Jython is just Python and you can use C or C++/Java libraries respectively with just a little bit of Cython/Jython syntax.
It's meant to speed up performance as well as improve code readability when a task would be more efficient to write in C or C++/Java and, this is done by using statically typed variables.

Or is Cython/Jython just some sort of extension that is used sometimes but not independently? What I mean is, you'd still write everything in Python and then, for the tasks you'd rather use C or C++/Java for, you'd use Cython/Jython instead? (I know I still need Python installed and similar things as it's dependent.)
Because if it really is better, other than the barrier that it's still being developed since it's rather new, wouldn't the need for C or C++/Java completely go away as these are as easy as Python but as powerful as C or C++/Java?
Jython is a implementation of Python language on the Java Virtual Machine, so Jython is Python but is not CPython. Cython is an extension to CPython and has not much in common with Python except some similarities in Syntax.
Is Cython/Jython an independent language?