Inverse text normalization (ITN) refers to conversion of spoken-format text to written-format text. Examples of this conversion are spelled-out numbers to digits, handling of emails and web addresses, and the display of some common units of measurement.
The following conversions are performed:
cardinals (numbers below thirteen are not converted; e.g. ‘one hundred twenty one’ → ‘121’)
ordinals (above nine, e.g. tenth → 10th)
decimals
measures (e.g. ‘one kilogram’ → ‘1 kg’)
dates
times
money amounts (e.g. ‘one dollar fifty cents’ → ‘$1.50’)
emails, websites (e.g. ‘twitter dot com’ → ‘twitter.com’)
phone numbers
credit card numbers