Computers are dumb. Despite all the talk about Artificial Intelligence, we’re not there yet.
The computers we work with, today, are just machines that execute the things we tell them.
And we talk to them using a programming language.
A programming language is a set of instructions and rules that we use to interface with a machine.
There are many, many different programming languages. You can even create your own, if you are into that. But more frequently you’ll want to use a programming language that others created a long time ago, made it perfect over time, and which just works without causing you headaches.
Every one of those languages solves a problem in a different domain or is particularly well suited in some situations.
Python and Ruby are mainly used on Web servers, or as more general purpose languages. Python is well known in the data science community, for example.
Swift, introduced by Apple, is the language used to create iPhone apps and in general all programs that run on Apple hardware.
I just mentioned those, but there are gazillions more. There’s no single “best” programming language. It all depends on the situation, on you and your team knowledge, the hardware it needs to run on, and other things.