I am given to understand that "crawdad" and "crayfish" refer to the same creature (or group of creatures resembling small lobsters that live in freshwater), and that the difference is dialectical.
Are these terms related at some origin? What caused them to become divergent? Is one closer or truerAccording to an original term thanWikipedia, "crayfish" becomes "crawfish" in parts of the otherUS (1), but what brought on the "-dad" ending change?