The users keep saying things like 'twelve thirty four' instead of 'one two three four'

Question

Users never just say "one two three four", they say "twelve thirty four" and things like that. I have a very complicated story about ABNF grammars and ASR engines but I'll just ask simply:

How can I generate a list of all the different ways someone might say '1234'? The number can be any number of digits.

I've seen numerous examples on how to expand a number in a grammatically correct way , but my users never use proper grammar. "10217" becomes "ten two seventeen". "78749" becomes "seventy eight seven fourty nine".