I am developing a new general-purpose programming language of my own design. It's currently my own personal project. I have read of some experts saying that new languages do not usually survive (unfortunately I can't find a reference to that right now). What are the most substantial problems that a new language faces? The language syntax is similar to C/Python families, it does not use S-expressions, and it is an imperative language, but I'm doing first-class functions in it to provide the facilities of currying.

In particular, I am concentrating on translating the source language to an intermediate language for execution by an interpreter, but I'm not in a position to translate to native code yet. What would be the issues with that? I've not personally used many non-native code languages, so I'm not well aware of the performance issues on today's machines.

I also can't decide upon a lexer and parser generator. What would be the pros and cons of Flex and Yacc vs. hand-made? And what benefits will LLVM provide? I need to get the interpreter ready as quickly as possible.

Finally, what factors will affect the language's use post release? I am planning a small library of essentials and full documentation for the first phase.