I find that many people have a tendency to spell by ear. That is, they listen to whether it "sounds" right. So the word may sound right but it has a meaning other than the one intended. Below are what I think are the most commonly misspelled words. They are not necessarily in order except for the first one, which happens to be my biggest pet peeve.
- there, their and they're
there = at that place (as in "over there"); their = possessive of they (as in "in their best interests); they're = contraction of they are (as in they're going to the store) - affect and effect
affect = to influence (as in "lack of sleep affected his test scores"); effect = to bring to pass (as in "her speech had a huge effect on the outcome of the vote") - weather and whether
weather = the state of the atmosphere; whether = if - stationary and stationery
stationary = not moving; stationery = paper and envelopes - capital and capitol
capital = a financial resource (as in "she had enough capital to open her own business"); capitol = a building in which a state legislative body meets - principal and principle
principal = chief or primary; principle = a fundamental truth or governing law of conduct - council and counsel
council = a legislative body; counsel = advice - it's and its
it's = contraction of it is(as in "it's a nice day"); its = possessive form of it (as in "the horse has its saddle on") - to and too
to = motion or direction; too = also. If you can put also in to replace the word, then it should be too - lead and led
The past tense of the verb lead drops the a (as in "I will lead the horse to water today, but yesterday I led the horses to water") - who's and whose
who's = contraction for who is (as in "Who's knocking at the door?"); whose = possessive form of who (as in "Whose shoe is this?")
