(Image Credit: Mike Marsland, Adam Berry/Getty Images

Samuel L. Jackson has a bone to pick with President Obama about the way the president sometimes addresses average Americans.

In the October issue of Playboy, the "Django" actor, in his signature style, upbraids the president for dropping "g's" off the ends of his words to sound more like the average Joe.

"First of all, we know it ain't because of his blackness, so I say stop trying to 'relate.' Be a leader. Be f***ing presidential," Jackson, a vocal Obama supporter last election, told Playboy.

"Look, I grew up in a society where I could say 'It ain't' or 'What it be' to my friends. But when I'm out presenting myself to the world as me, who graduated from college, who had family who cared about me, who has a well-read background, I f***ing conjugate."

A Morehouse College graduate, Jackson, 64, lamented how commonplace "street language" has become.

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"The other day I'm watching this white guy talking to black people on TV, and all of a sudden he's saying stuff like 'Pump your brakes' and 'I got you,' these new politically cool terms that kind of came out of hip-hop and blackness," Jackson told Playboy. "I'm thinking, 'We do still speak English, right?' Though sometimes I wonder. … The whole language and culture are different now."

But that doesn't excuse bad grammar in Jackson's eyes.

"I'll be reading scripts and the screenwriter mistakes 'your' for 'you're.' On Twitter someone will write, 'Your an idiot,' and I'll go, 'No, you're an idiot,' and all my Twitterphiles will go, 'Hey, Sam Jackson, he's the grammar police," Jackson said.

"Somebody needs to be," he added. "I mean, we have newscasters who don't even know how to conjugate verbs, something Walter Cronkite and Edward R. Murrow never had problems with. How the f*** did we become a society where mediocrity is acceptable?"