mammy vs mamma

mammy and mamma both are nouns.

Word	Noun	Adjective	Verb	Adverb
mammy	Yes	No	No	No
mamma	Yes	No	No	No

As nouns, mammy and mamma are synonyms defined as:

Other synonyms of mammy include ma, mama, mom, momma, mommy, mum, mumma, mummy.

mammy (noun)	mamma (noun)
informal terms for a mother	milk-secreting organ of female mammals
an offensive term for a Black nursemaid in the southern U.S.	informal terms for a mother