"Guinea" is an American slang term for an Italian.
At the time of massive Italian
immigration to the U.S. in the late 19th and early 20th centurys, most Americans lived on farms, and used a large fowl called a Guinea to keep the garden and lawns free of bugs and ticks, which they ate in great numbers.
A flock of Guineas "spoke" in a rapid, excited manner, and the newly arrived Italian
immigrants spoke in a fast emotional manner that reminded
the Americans of the sound that a Guinea fowl made, so the newcomers were soon dubbed "Guineas" by the local people.
(Son to
Father) "Hey Pa, them I-talians sure do talk funny!"
(
Father to Son) "That's rightly so boy, they strut around and babble like a
gaggle of Guineas!"