I find languages are pretty easy to pick up after the first few. What seems to be the barrier nowadays is frameworks. How do people go about learning a new framework? Obviously most of them have an intro project to follow on with, but they tend to be pretty simplistic, and once that's done, getting to the complicated bits that you actually want to implement seem to be the barrier.
Re-implement a toy version of the framework from scratch. :-) Or, try to add a non-trivial feature to the framework.
It seems to me like you've already solved the issue of "learning the framework" if your mental model of the framework is that solid.