Why should anyone learn a programming language? I suppose the reason is because you want to use it to control a computer.
So, maybe you should learn to control the computer first. However, it's not done that way. It's like when you learn to drive, you do it in a car. So, which car should you learn first? If you learn to drive a Toyota will that make it easier to learn to drive a Honda?
The analogy isn't perfect. Cars are designed to have similar controls. Programming languages are NOT designed to make it easy to go from one to the other, but the general concepts of programming remain the same -- and that's because, after all, the purpose of learning a programming language is to learn how to control the computer -- and the hardware doesn't change when you change programming languages.
Many languages are based on C, and parts of programs written in such languages can be identical. Usually, when there are differences among C-based languages, it's with the input and output statements.
Meanwhile, unless you are in a course, you don't need to memorize the syntax of every language. And, even in a course, many will give open-book tests, because memorization is NOT the purpose of the course. The book won't help you if you haven't already learned the concepts.
If you are hired for an entry-level job, they do not expect you to have learned anything beyond your courses. It will take 3 to 5 years working full time at a programming job for you to be considered an expert.