Comment by kylebgorman

"text normalization" just refers to that sort of thing. it's a subcomponent of the "front-end" of a speech synthesizer but it can also be used for speech recognition (if your training data contains things like "145" you may want to convert it to read "one hundred and forty five", for various reasons) and information extraction (perhaps you want to treat "145" and "one hundred and forty five" as the same).