Do you know what a homophone is? (Clue: it has nothing to do with homosexuality or homogenised milk.)
Homophones are words which are pronounced the same as one another (i.e. they sound identical), but which mean different things, and are often spelt differently. People often confuse homophones with one another, such as when someone on Facebook says “your beautiful”, when what they actually mean is “you’re beautiful”.
But today’s homophone example is one that even copywriters have to pause and think about. And that is the classic dilemma of “affect” vs. “effect”.