A programming language is a formal language used by programmers to develop various kinds of output such as softwares and scripts by inputting a set of instructions.
The first high-level programming language was Plankalkul, created by Konrad Zuse between 1942 and 1945 for the purposes of engineering. The language was initialy described in Zuse's planned Ph.D. dissertation in 1943 and later developed in 1945. The main features of the programming languaage was that the functions don't support recursion, only supports call by value, only local variables, composite types are arrays and tuleps, contains conditional expressions, contains for loop and a while loop and no goto.
The 1960s and 1970s were the time when most programming languages model that we use today were invented.During this period, there was a considerable debate regarding the usage of structured control flow structures of selection and repetition, block structures and subroutines in contrast to using simple tests and jumps. This debate was due to some languages not includeing a "goto" at all, which forced structured programming on the computer.
Pull requests are the amount of code being written in a certain language.