Personally, I believe that you learn any language not by studying the books, but when you actually start using it for a job/task/lesson/whatever...
It's no use learning about hashes,for example, if you don't use them in a project... You will forget them in a couple of days. So, if you are not going to use Perl in your work or a lesson, or something else, what's the use of learning it?
If, on the other hand, you are going to apply it, trust me, you will learn it much better each time you want to complete a task...