Anachronism-checker

Verbal anachronisms plague historical fiction, especially screenplays. It spoils the realism of a Civil War battle scene to hear a captain call his sergeant a "moron" when you know the word "moron" wasn't coined until 1910. Writers need something like a spell-checker that flags any word or expression that is inappropriate to the period of the work. (Better still, it might suggest an appropriate synonym, such as "blockhead.")

A modification to a conventional spell-checker could do the job. First, for any given project, you'd need a word list that contains only words that were in use in a certain year. You could compile such a list by scanning several books, newspapers and magazines that were published in that year. Fortunately, these are now abundantly available (up to 1923 anyway) thanks to Google Books, Project Gutenberg, the Internet Archive, and so on.

By merging many such lists from different years, you could create an all-purpose list where each word is tagged with a range of dates—the earliest and latest year the word was found in your corpus. Then, when you begin to check your manuscript, you specify what year you are portraying, and the program does the rest.