I know there was already a thread created on the pet peeves many of us have regarding forum posters misuse of words and improper spelling.
But after reading, Chris Shugart's cool tip of the day regarding the use of "loose" vs "lose" I feel compelled to reiterate the one that drives me up the wall the most.
People, it's spelled "ridiculous" with an i dammit. It's not "rediculous". When you spell the word that way (e.g. "rediculous) you sound "ridiculous". God, that gets under my skin. Learn how to spell. You come across much more intelligent by doing a simple spell check before posting. Rant over.
Repeat, the most general term, means "say, do, perform, or experience something or express oneself again in the same way or with the same words as before." (Repeat can also mean "recite something from memory or tell it to another.")
Iterate is more formal; it can also refer to a computational process for arriving at a specific result by repeating a set of operations through a series of increasingly close approximations.
Nowadays, iterate tends to be used for repeated actions, especially in mathematical functions, and reiterate is far more common (it must just sound right to us) and tends to be used for things one says, especially when repeated--er, over and over again.
"Reiterate," which was first recorded in 1526, does sometimes convey the idea of many repetitions, but more often it is distinguished from such common verbs as "repeat" and "restate" by connotations of forcefulness and emphasis.
Considering the nuances behind the meaning of iterate and reiterate as it is and should be used in every day language, I believe I correctly used the word "reiterate" to forcefully state and emphasize my utter disdain for the misspelling of the word "ridiculous"
About the iterate/reiterate debate, one thing about English, you can't count on all the rules being followed. Consider the prefix "in," which usually means "not" as in "inconsistent." However, "invaluable" means essentially the same thing as "valuable." Same with flammable/inflammable.
Usage, fortunately or unfortunately, also has bearing on a word's meaning. Consider the word "decimate." Technically it refers to killing or destroying every tenth person or thing. Common usage has now made it a synonym of obliterate. How you change a wor'd meaning from destroying 10% of something to destroying practically everything I don't know. Somewhere along the way, common usage added the additional 89.9% of destructive power.
As for reiterate, it's technically a synomym of repeat. I've always used it as repeating something for emphasis. I may have actually read that as one of the definitions somewhere. So, if I reiterate something, I don't think of it as being simply repetitive but as being repetitive to emphasize something important. Perhaps my usage has been wrong all these years.
Unless we want to consider "sharpen up" as a common idiom. In this case, the word "up" is an integral part of the "sharpen up" idiom, and as such, is not necessarily subject to the tsk-tsking we do when finding a sentence ended with a preposition.
"What do I have to sharpen up for?"
Now that's ending a sentence with a preposition... and bad form.