One task that comes up from time to time, especially in financial applications, is the task of rendering a numeric value in words -- for example, 123 is shown as "one hundred twenty-three". Writing a routine to do this in English is trivially easy, but generalizing it to work with ANY language is surprisingly complicated.

This task describes the novel solution to the problem used in ICU: A "programmable" number formatter based on a simple yet expressive description language that lends itself well not only to spelling out numeric values in words, but to a wide variety of other number formatting applications.