Creating New dynamic programming language ?

Well depends on the type of language but in simplest terms what's really being designed and created is the compiler or interpreter. Deciding upon what syntax and language will translate into what machine code or assembly language. Of course if you're working at assembly or machine code you can see why creating a whole new language is a massive undertaking. But the key here is creating the compiler, that's really what is meant by a programming language. Although of course there are exceptions to that if it's a higher level language with interpreter and of course maybe you just want to create an API and your own scripting language for an application. But even those are basically using some kind of parser and compiler.

One link you might find interesting http://www.drdobbs.com/architecture-and-design/so-you-want-to-write-your-own-language/240165488

Thanks I want to design a simple language just to understand what is going on.