Dictionaries

Is it possible to add new words to the English dictionary? It seems as though no proper nouns(names of months, city names, etc) are in the current dictionary. I know about the EXTENDDICT variable, but I would prefer to update the current dictionary rather than have every user add these words to their personal dictionary. Or is it possible to use a list of several files somehow with EXTENDDICT?

John Dorsey
johnsdorsey@yahoo.com