Programming languages are typically created by designing a form of representation of a computer program, and writing an implementation for the developed concept, [1] usually an interpreter or compiler.
Interpreters are designed to read programs, usually in some variation of a text format, and perform actions based on what it reads, whereas compilers convert code to lower level.
It's important to consider the target audience of a language, its unique features and its purpose.
[2] Compiled languages converted to machine code, tend to be a lot faster, as lower level operations are easier to run, and outcomes can be predicted and compiled ahead of time.
[9] Processes of making a programming language may differ from developer to developer; however, here is a general process of how one might create a programming language, which includes common concepts: