The English language may be complex, but it offers users an expansive vocabulary. The benefit of that isn’t the ability to impress people with five-syllable words; it’s the remarkable precision that all those words make possible.

But English also has convoluted rules of phonetics. And one place people – including professional writers – tend to get tripped up is in the area of homonyms. If your memories of third grade have become a bit hazy, homonyms are words that sound alike, but are spelled differently. More important, they have vastly different meanings – and your trusty spellchecker isn’t smart enough to recognize whether you’ve chosen the right one.

I recently read an excellent book by a skilled writer. Unfortunately, though, he had a problem with homonyms, and his editor seemed to share the problem.  The example that finally pushed me over the edge was when he mentioned that someone wasn’t “aloud” to do what he wanted. Yes, “aloud” and “allowed” sound identical, but their meanings are so very different. To some, I’m sure it’s not a big deal, but to this reader, it undermined the writer’s credibility and expertise.

Their, they’re, and there are three words that are regularly interchanged. Few people seem to grasp the subtleties of affect and effect. Principle and principal are both misused so often that it’s only matter of time before they mean the same thing. (I’ve even seen school administrators include tenure as a “principle” on their resumes, which would be enough to prevent me from hiring them.)

If you don’t know the differences in meaning, learn them before you use these words, because your writing will become more precise and effective. If you do know the meaning, read and reread what you write. Don’t trust the spellchecker!