How did Roman's use numbers in their everyday speech? We know that 5 is "Five", and 25 is "Twenty-Five" because of our numbering system, but with IX being "nine" and IXX being "nineteen" and IXM being "nine hundred eighty-nine", how did they actually speak the numbers they wanted to?
By saying the word for the number. I mean, we don't say "9" (whatever that would sound like), we say "nine", or more technically, "9" is an abbreviation for "nine". With Roman numerals, "IX" is just a shorthand for novem - nine.
Also, IXX and IXM are not numbers. XIX is 19, MIX is 1009, and 989 is CMLXXXIX.