What is the most effective way to learn a software language?

I say the shortest way, of course, how short it depends on your ability to use it: using that language. Actually, if you ask me, there is no such thing as learning the language. There is comprehension. You have to comprehend the logic of the programming language. More importantly, there is an algorithm. If you are able to settle the algorithm in your mind, if you have understood how to apply the algorithm you have installed to the language you want to use, I think you can already use the language. If you've never programmed before, I recommend you taking some kind of introduction to programming course before learning a language. In this training, you start to think "like a programmer" by learning the most basic algorithms.