Follows the perception post nicely, don't you think? And here's the gist: say what you want, someone will always disagree.
Do you say toMAATo? No, I sa toMAHto.
Do you say PILLow? No, I say PELLow.
Do you say MOHNster? No, I say MUNster.
Does this mean we can't get along?
Unfortunately in life, small differences like these often mean people can't get along. Small differences can be the last straw in a political debate or the final word in a family argument. Small differences can be huge.
And in writing, small differences can mean big changes for a character. How your characters pronounce words can show readers where they're from, from which economic class they hail, and even the nature of their job.
In addition to pronunciation, you can also express these things in choice of words. Does your character use words like "obfuscate" and "propensity?" Or do they stray toward "fuck" and "turd?" (I know you're all laughing right now--I sware those are the first two that popped into my head!)
Regardless of your choices, what your characters say and how they say it say something. It's part of the characterization of your protagonist, antagonist, and supporting players.
How do you use language in your writing?