Carribean = Ca-rib-BEE-an (slight emphasis on 3rd syllable) in UK.
US = Cu-RIB-ian as I remember.

that word has long given me angst, and i try to avoid saying it altogether (really, i do ).

from what i can gather, USans do say cu-RIB-ian, but word to the wise: if you call the disneyland ride "Pirates of the Cu-RIB-ian", your friends and family will laugh at you . evidently it's an iambic quadrameter (?) thing, dunno.