why do some people call green peppers mangoes?

I have heard people from Lima, Ohio refer to green peppers as mangoes. How did that come about?

Solution 1:

It appears that:

“When mangoes were first imported to the American colonies in the 17th century, they had to be pickled due to lack of refrigeration. Other fruits were also pickled and came to be called ‘mangoes’, especially bell peppers, and by the 18th century, the word ‘mango’ became a verb meaning “to pickle.’”

green peppers "mangoes."

Solution 2:

I’d never heard of such a crazy thing in my life, but the map below shows why: I’ve never lived in the places where this occurs. The Dictionary of Regional American English (DARE) explains that this way:

1. Any of var fruits or vegetables (as a muskmelon, peach, pepper, or cucumber) filled with a usu highly spiced stuffing and pickled. [OED mango sb.¹ 4 1699 →; the East Indian mango (Mangifera indica) was at first known only as a pickle; the “mangoes” illustr here were made in imitation of that imported delicacy.]

2. also mango pepper; pronc-sp mangle: A pepper, esp a green pepper 1. chiefly W Midl See Map

3. also mango melon: A melon (Cucumis melo Chito Group). [See quot 1988] Also called vegetable peach

There are more citations and examples given at the link above.

By the way, a bell pepper like the green ones you mention (Capsicum annuum) is called a capsicum in Antipodean English. They’re apparently quite generic about the whole business there.