We moved from punch cards to programming languages because punch cards were slow, difficult to use, and easy to make mistakes with. Programming languages made it easier for humans to give instructions to computers using words and symbols that are easier for us to understand. This shows that the purpose of programming languages is to make communication between humans and computers easier and more efficient.
We need many programming languages because different languages are designed for different purposes. Different languages also have different strengths and weaknesses. Having many choices allows programmers to choose the language that works best for the problem they are trying to solve.
One programming language I use is Python. One drawback is that Python can sometimes be slower than languages such as C or C++. For example, if I had to process a very large amount of data or perform many calculations, Python might take longer. I would like Python to be faster while keeping its simple and easy-to-read syntax.
I would first learn how to create a programming language. Then I would decide what I want the language to be used for and define its syntax. Then I would decide whether to use a compiler or an interpreter to execute it. I would also have to set up standard libraries and functions for it.