"And people say, 'Oh, you slur, you slur,' and I go, 'Yeah, because it only half-works. Give me a break, ya' know? I don't do it intentionally.
"People didn't understand what I was saying for many, many years. Still don't!" he laughs.
Some mistook that for stupidity, including his own father.
Rocky Balboa: "My dad told me, 'You weren't born with too much of a brain, so you better start using your body.' So I become a fighter!"
"That was actually something that your dad said to you?"
"Yeah. A lot! 'You weren't born with much of a brain, so you better develop your body.' And it stuck."
When he was 12 he saw "Hercules," staring Steve Reeves, and that changed everything.
"I flipped out. Flipped out. Out of that theater, I literally ran to a junkyard, where there was pieces of metal that resembled a barbell. And I started looking for drive shafts and wheel wells and brake drums and I started stringing things together with rope."
His family moved to Philly, where Stallone spent his teenage years bulking up, before heading to New York to give acting a go.
They were lean years, to say the least. He even sold his dog, because he couldn't afford dog food. "Absolutely! $50 at a 7-Eleven."
Eventually his bulk started paying the bills. He was cast in "Bananas" as the guy who mugged Woody Allen on the subway. He was also the mugger who GOT mugged by Jack Lemmon, in "The Prisoner of Second Avenue."
But nothing really clicked.
"That's when I realized I'm never going to make it in acting per se. I have to find some other niche, something."
That turned out to be writing. "All I did was write and write and write and write, maybe 30 screenplays, of which 29 are probably horrible, but it's the process of completing them that mattered."
He completed the screenplay for "Rocky" shortly after his 29th birthday, writing the world he remembered back in Philadelphia.
"Put it this way, all the clothes in 'Rocky,' were mine," he said. "Even the hat, everything was mine."
Studios loved his script, but Stallone had a condition: He refused to sell the rights to his film, unless HE was cast in the lead role.
Cowan asked. "You had no money and people were offering you hundreds of thousands of dollars? And you were turning it down?" Cowan said.
"Yeah. It went up to about $360,000, which is crazy!"
It turned out to be a sure bet. "Rocky" went on to win three Oscars, including Best Picture. Sequels started rolling out almost every few years.
But the fame took a toll on his personal life. Stallone went through a divorce, married actress Brigitte Nielson, but got divorced again after just 19 months.
All while Rocky was morphing into another character; Stallone calls Rambo "Rocky on caffeine."
The script for "First Blood" had been bouncing around for years. "I was the 11th choice," Stallone said.
"Yeah, they were just about ready to hire a chimp! And then I came along."
Again, Stallone had some demands. In the original script for "First Blood," Rambo dies. Stallone wanted the ending changed.
"There's a lot of vets, that look at this and say, 'There's no reason to go on. Look at this character representing us, and then in the end he gets shot?' I thought this was irresponsible on my part."
Rambo: "Nothing is over! Nothing! You just don't turn it off! It wasn't my war! You asked me, I didn't ask you! And I did what I had to do to win! But somebody wouldn't let us win! And I come back to the world and I see all those maggots at the airport, protesting me, spitting. Calling me baby killer and all kinds of vile crap! Who are they to protest me, huh? Who are they? Unless they've been me and been there and know what the hell they're yelling about!"
Col. Trautman: "It was a bad time for everyone, Rambo. It's all in the past now."
Rambo: "For you! For me, civilian life is nothing! In the field we had a code of honor: you watch my back, I watch yours. Back here there's nothing!"
It made millions at the box office. Within a few years, the man some thought was challenged as a child had written his way into two movie franchises.
As his characters matured, so did he. He married again -- this time happily -- and kept writing, even directing.