mammy vs mummy

mammy and mummy both are nouns.

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

As nouns, mammy and mummy are synonyms defined as:

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

mammy (noun)	mummy (noun)
informal terms for a mother	a body embalmed and dried and wrapped for burial (as in ancient Egypt)
an offensive term for a Black nursemaid in the southern U.S.	informal terms for a mother