Today’s word peeve (I can’t help it; deadlines make me peevish): a couple of not-exactly-homonyms, affect and effect.
People mix these up a lot, and it’s not really surprising. They look exactly alike except for that initial vowel, and in spoken English the difference between those unstressed vowels becomes even more obscured. Just to add another layer of confusion to the vocabulary cake, each of them can function both as a verb and as a noun.
It works like this:
Effect has its ancestry in the Latin verb facere, meaning to make or do or bring about (plus a host of related extended meanings), plus the Latin prefix ex-, meaning from or out of (among other related things.)
Effect-the-noun, accordingly, is something that is made or done or brought about: One effect of the hurricane was a prolonged power outage.
Effect-the-verb is less common; it means to cause or bring about something: The new mayor hopes to effect some changes in local disaster response policy.
Affect also goes back to that same Latin verb facere, this time with the prefix ad-, meaning to or toward.
Affect-the-verb is the more common one here; it means to do something or cause something to happen to someone or something else: The hurricane will affect the east coast from Maine to the Carolinas.
Affect-the-noun is the least common of the lot; it’s mostly used in psychiatry and related disciplines, and refers to the outward manifestation of someone’s inward state. A person who isn’t showing much by way of such outward manifestation has a flat affect — his/her affect, in this case, is the behavior that he/she is turning toward the world/the observer. Most of the time you won’t need to worry about this one.
(As you probably have guessed, I’ve got hurricanes on the mind right now. I’m not in the storm’s current path, but I know people who are.)