"palabla" sounds like "para habla" (means "for speaking"). There are some similar words like "paraguas, parachoques", but it seems that "para-" here means "parar" (that is, "stop") but not "para". So, "pala-" in "palabla" is different from "para-" in "paragua".
I'd like to know wether "pala-" is a prefix in Spanish or not. If that's true, where is it from and what does it mean? Could you teach me?
Some useful links are para- elemento compositivo, wiki para- and wiki pala-.