Why is it so important?
Because our brilliant mind can auto-translate and buzz over misspelled words without us even knowing it. Reading your book isn't good enough, because the mind works too well and efficiently: you need to slow yourself down, and reading out loud does that. It forces you to go line by line.
Take, for example, this little beauty I picked up in my own book after reading it to myself, oh, seven or eight times:
I pulled Bill
back a bit. “What the hell are you
doing?”
“Giving you a
chance,” Bill said.
“Yeah, but this
isn’t really a ‘giving you a chance’ kinda moment. This is serious stuff.”
“Do you
honestly think there’s anything out there you can’t handle? Worse than the lake? Worse than what you told me about in
Pittsburgh? You’ve seen the worst nature
has to offer, and you’re still here.
Anyone who can cover the ground you’ve covered, keeping his team intact,
is ok with me.”
I stood there,
frozen and confused. Me? I looked around the room. Ashley didn’t smile, she just put her two
pistols into her jeans. “He’s right,”
she said.
Louie looked
down at his shoes. “I don’t want to go
with anyone else.”
Tommy hoisted
his sniper rifled on his shoulder and gave me a nod.
The general
shook his head. “Not these three. Bill - for chrissakes, they’re just kids.”
“Not anymore
sir. They stopped being kids a long time
ago.”
No argument
from anyone. The room grew quiet. “Fine.
Bill, you’re in charge, Dawson’s second in command. Get those people organized and get ‘em
ready. Let’s move.”
Did you catch it? Don't feel bad if you didn't, like I said I buzzed over it seven or eight times. Spell check accepted it because it's a real word (although it doesn't make any sense in context), and my mind saw it and instantly dismissed it because it knew what it should've said.
If you read it out loud, you go line by line. Slowly. And then you catch it:
Tommy hoisted his sniper rifled on his shoulder and gave me a nod.
RIfled. A d. One simple letter that doesn't belong.
There were plenty of other examples that I caught by reading the book out loud. It does take time, it slows you down to a crawl and burns inside your "get this thing out as quickly as you can" center, but it's well worth it. Trust me.
So read it out loud, and WRITE ON!