関西弁 (Kansaiben; or Kansai dialect) is a Japanese dialect that originate from Kansai / Kinki region in Japan. Kansai dialect is typified by the speech of Osaka, the major city of Kansai, which is referred to specifically as Osaka-ben. It is characterized as being both more melodic and harsher by speakers of the standard language.
Some of the translators on Danbooru and sometimes even professional dub voice actors translate this accent to a southern U.S. accent in English.