One of my friends from grad school is from Canada, and when she first came to Oklahoma, she had the uncontrollable urge to pull words out of people's mouths because Oklahomans talk too slow. I can't confirm or deny if we talk slower than people elsewhere, but I don't think that's the only speech quirk we possess.
A recent NPR article discussed lost regional colloquialisms. (Oklahoma's was larruping. It's not lost though, my mom still says it.) Another recent article from NewsOK.com asks if the "Okie dialect" is disappearing. (Considering Okies were very poor migrants who left Oklahoma during the Dust Bowl to find jobs, I'd say their dialect is dead, you know, because there are no Okies anymore. But I digress...) Anyway, from NewsOK.com: