Alignment indices for text normalization
I wanted to know if it's possible to get the indices for text normalization for semiotic classes. For example if I have a text
```
I was born in 3/7/1989.
```
which normalized to:
```
I was born in March seventh nineteen eighty nine.
```
The index of begin and end of the text part "3/7/1989" have the correspondence in "March seventh nineteen eighty nine" in the second one.

I want to have a function that give me the indices (start, end) of the input text aligned with the (start, end) in the normalized text. 
