Copy editors learn early in their training to distinguish commonly confused words. Stylebooks and writing manuals have entries and lists of such words. One of my favorite books is "Working With Words," by Brian S. Woods, James L. Pinson and Jean Gaddy Wilson. I have a 2003 printing of the book, and Chapter 8, titled "Usage," has two helpful lists: Misused Words and Mistaken Phrases and Confused Words.
On the list of confused words, for instance, are tocsin (a disaster signal) and toxin (a poisonous substance of plant or animal origin) and reluctant (unwilling to act) and reticent (unwilling to speak). Writers and editors can easily mistype or overlook these and other words on the list in a deadline rush. That's why copy editors are important as one last editor to read a story before it is published. Accuracy is essential to journalism, and I see correct word choice as part of accuracy. If we mean that someone was unwilling to speak, we must describe him as reticent, not reluctant.
The newest Grammar Guide quiz deals with word choices such as this. The sentences would not be understood the same way if the word choice were different.
Try the quiz. It's only five sentences long, so you can finish it in a few minutes and read the explanations for the answers. Click here or on the question mark icon to begin. I invite you to comment on this post or to send me a note.