mammy vs mommy

mammy

noun
  • mamma; mother 

  • In the southern United States, a black nanny employed to look after white children; or in the antebellum South, a female slave who was close to the household and looked after the children. 

mommy

noun
  • Mother. 

verb
  • To treat someone like a mother would; to mother someone. 

adj
  • Characteristic of a mother; motherly. 

How often have the words mammy and mommy occurred in a corpus of books? (source: Google Ngram Viewer )