Thew and Fro

Spell checkers allow users to add words to their dictionaries. It would be nice if they would also allow users to subtract words. Two frequent typos of mine are 'thew' for 'the' and 'fro' for 'for'. Unfortunately, both typos are English words, though neither is a word I use at all often. Almost always when either occurs in my writing it's a typo. So why can't I tell ispell or Open Office or Firefox or Thunderbird that these are words that should be flagged as misspellings? Actually, I could write a postprocessor for LaTeX documents that flags likely typos, but it would be harder to do this for a clumsier tool, like the WYSIWYG tools. Also this points out a problem with non-text-based tools for text-based applications. A postprocessor would work fine for text files, which means it would be more widely applicable than to just LaTeX, but every GUI has its own spell checker, with its own dictionary, and so they don't integrate well with each other, with simple tools, etc. Going back to elm or mutt for e-mail would solve part of this problem, by raising my productivity for basic e-mail by allowing the editing of e-mail in emacs, but they make multimedia e-mail a bit more of a challenge. OTOH, perhaps they've improved attachment handling in the past few years--worth a look.