From my (non coder) point of view it's hard to understand what drives the continual expansion in programming languages. Is there a general principal for creati

From my (non coder) point of view it's hard to understand what drives the continual expansion in programming languages. Is there a general principal for creating a whole new language as opposed to adding features.? Could you have a language where you could have a setting for something like static typing vs dynamic typing? The language would get more complex, but seems like it would still be less complex than a whole new syntax?