George Lucas posted:

It is in my opinion important to keep your film making rooted in your own experience and I had never known a seven foot tall dogmanthing so I based him off of my grandfather, Pappy Lucas,, the most be-haired person I’d ever known, touching him was like running your hands through a sheep, and who spent his days sitting on the front porch chewing tobacco. And I knew then I needed a seven foot tall dogmanthing named Chewto Bacco, but the studio thought it was better to shorten it to Hans Solo. Anyway then we hosed up and gave Harry the script for the that character and he memorized all the lines before we realized and we had to scramble and switch the characters around. So that’s why Chewbacca isn’t the suave smuggler captain as I originally intended.