So, which word do you use? My impression has always been that “barefooted” has a bit of a retro feel about it.
Anyways, Google now has a new tool, their Ngram Viewer. This searches through all of the books they have scanned and counts up the occurrences of the words you ask for.
Here are the results for “barefoot” vs. “barefooted”:
It appears that my impression was correct. Up until 1920 or so, “barefoot” and “barefooted” ran neck-and-neck, mostly. But suddenly in the 1920s, “barefoot” took the lead and rushed ahead, leaving “barefooted” in the dust.
I really don’t know why. But I can make some guesses that are pure speculation (and feel free to comment to leave your own guess). The 1920s is about the time when rural areas really started to industrialize. Rural electrification and radio started to spread, and even in rural areas folks were expected to wear shoes. As bare feet disappeared, they were discussed less, and the simpler, and more regular, “barefoot” came to the fore.
Also notice the jump in “barefooted” starting around 2000. I wonder if that is somehow related to media publicity the Society for Barefoot Living started to get around that time? As bare feet were talked about more, maybe that allowed more room (so to speak) for the alternative form.