Spellcheck will be the downfall of our civilization. I am convinced of it. No one checks to see if they are using the correct word anymore, and this can be dangerous when it comes to the English language, which has so many words that sound alike but are spelled differently and mean very different things. Here are some examples that I see all the time on the intertubes:

Populous — populace. One is an adjective indicating a geographical location has a large number of people living there. The other is a noun referring to the people living in a geographical location. Here they are used in sentences:

• Great Britain is a very populous nation.
• The populace of Great Britain is fond of fried potatoes.

Discreet — discrete. These are not the same word. One means modest, unobtrusive, circumspect, protective of privacy. The other one means (in general usage) something separate, distinct, discontinuous. (It’s also a math term but I’m not going to go into that because Math Is Hard.) Anyway, here are a couple of sentences:

• Cindy was known for being discreet, so all the women told her their secrets.
• Mark opened the box and a discrete number of parts fell out that did not appear in the instruction manual.

And from a reader: a confusion of whelp with welt. Again -- aargh! they aren't even pronounced the same! Anyway, here are both words used to show their meanings:

• "Get out of here, you young whelp!" the farmer yelled after the mischievous neighbor boy he had caught stealing apples. It's also the word for a young animal as well as a human child, and when one says "the bitch whelped last night" they are talking about their dog who had given birth to puppies.
• As for welt: "Tina winced as she applied calamine lotion to the welts the poison ivy had caused." A more obscure usage is using "welt" to refer not just to the injuries being beaten with a leather strap can cause, but to the strap and to the act of beating a person with it. Another meaning of "welt" is "a strip, as of leather or other material, stitched into a shoe between the sole and the upper" and "a tape or covered cord sewn into a seam as reinforcement or trimming." (All definitions from the Free Dictionary, which more people should use.)

Stay tuned, I'm sure there'll be more!