Python

I understand why you ask this question, but really the fastest way to learn is to decide what you want the computer to do and start looking for that.

One thing will lead to another and you'll learn lots of things that way, while you're immediately using it.

Tutorials and courses can work, but usually it works best if you use whatever you are learning.

So come up with an idea for a program, and start building. There will be mistakes, anger, frustration and cursing involved, but you will learn a lot.

First at the lower level, and later on you will probably start wondering how to structure it all. And then you'll learn about that too.

My point? Just dive in, fall on your face a couple of times and you'll learn a lot in a short time.