History of programming language

In the 1950s a German mathematician was able to develop a high-level programming language, in which the low-level code was built,
Assembly is a low-level programming language (hardware-related) that was more commonly used for computers at that time,
IBM Machine Systems Inc. developed the first commercialized high-level programming language (fortran) called fortran, a fortran scripting language built with assembly-only code later the languages ​​pascal, basic, and so on.

Built one by one in assembly language, Dennis Ritchie (computer scientist) eventually developed a language system called Unix, which consists of several programming languages ​​called assembly, algol, fortran, and All of them were written or assembled in assembly language then all computer engineers switched to this language because all operating systems were in this commercial language and the language more comfortable and better than the rest of the algorithm in C programming language to be after another programming language such as Python was written with the language and C++ and C# and PHP and …
C++ is a language directly related to C that can be written in graphics language. Built in Bell Labs.
Almost all graphical operating systems are made of C++ and the kernel is written with C such as android (based on linux), ios (based on FreeBSD and MacOS), macOS (based on freebsd and NeXTSTEP), debian (based on linux), windows (based on DOS/OS with a few changes),

what is the purpose of PLP anyway? And what is he going to do?