Sometimes one needs to produce a text in which many numbers have to be written out in words. Writing such a text and ensuring it is error-free can be a burden, especially if the author is not fluent in the language. Such may occur when working on a reference grammar, a research paper or presentation, or a problem on number names for a contest in linguistics. A remedy is to prepare the text with TEX and let some parts be generated automatically. The human effort this takes is to compose a grammar that describes the features of the numeral system. This paper discusses how this is done.