According to Wikipedia, that venerable and revered source of all Internet and planetary knowledge, a nursery rhyme has its history in English plays that originated in the mid’16th Century. The publisher, John Newbery, issued a book of English collections before 1744 called Tommy Thumb’s Song Book, followed by Tommy Thumb’s Pretty Song Book. Newbery’s stepson, Thomas Carnan, is credited with being the first to use the term “Mother Goose” for nursery rhymes. Nursery rhymes comprise one sub-set of story genres.
A genre is a term used to classify kinds of literature and music. For example, “detective” stories comprise a genre that is different than “cowboy” stories. “Country western” music is different than “gospel” music, and so on. Of course, genres are often loosely defined, with overlap between them: a detective story genre may be mainly about cowboys and gospel music genre may include western themes. Literary genres include, for example, poetry, prose, fiction, non-fiction and drama, each with sub-genres as well. Nursery rhymes are a sub-category of literary fiction.
Within a given cultural tradition, as in language groups of Papua New Guinea, stories can be categorized generically and individually. For example, the Kewa (of Papua New Guinea) use the words iti and remaa to represent folklore on the one hand and history on the other. Oral societies provide their history by means of folk stories and folk history, for example, by means of genealogies and classifications, for example—blood v. marriage kin (consanguine and affine).
Stories are live representations that impress listeners more with their images than with their propositions. For example, “Mary had a little lamb” is a proposition, but “Its fleece was white as snow” provides the hearer with a mental image.
Stories are also idiomatic, i.e. they are told in the vernacular with cultural analogies and background information. They are therefore often imaginative, not just in the sense of say telling my granddaughter a story, but also in her mind as she forms mental images of Mary and the sheep. They also include particular themes, plots, sub-plots—“and everywhere that Mary went the lamb was sure to go.”
Although stories may be historical and built on what the teller views or represents as things that happened, nursery rhymes are purely fictional. Nevertheless, they are dynamic and can be converted into drama or song to represent various aspects of the story. They are often short and pithy, accompanied by animation, drama, and so on. Nursery stories are generally for the very young, but can be adapted according to audience backgrounds, such as for ethnicity or gender, and are often instructive, either directly or indirectly, with particular cultural applications and morals.
Nursery rhymes were composed for children and include poems, lullabies, finger plays and counting. Many rhymes are classic and therefore old, for example: 1) Baa, Baa, Black Sheep, 1731; 2) Goosey, Goosey Gander, 1784; 3) Jack and Jill, 1765; 4) London Bridge is Falling Down, 1744; 5) Mary, Mary, Quite contrary, 1744; and 6) Three Blind Mice, 1805.
Other nursery rhymes may involve counting or singing include, such as: 7) wheels on the bus; 8) Eeny, Meeny, Miny, Moe; 9) Little miss Muffet; 10) Row, row, row your boat; 11) Itsy bitsy spider; 12) Peter, Peter, pumpkin eater; 13) Little Bo Peep; 14) Four and twenty blackbirds; 15) Pat a cake; 16) Little boy blue; and 17) Hey diddle diddle.
Because nursery stories are entertaining, they are sometimes told by professional storytellers. Although the intended message of a nursery story is not always apparent and may require interpretation, it will probably spoil a nursery rhyme to provide detailed exegesis—so consider many of them “spoiled” by me. However, even as a linguist, I am mindful that a child is not interested in the story’s semantics, pragmatics or theology, noting such things as actors, agents, settings, background and deixis.
Nursery rhymes can be ad hoc and provocative, whereby one story leads to another—a chain of imagination, such that a story acts as a “trigger” for another.
In summary, nursery rhymes combine various elements:
media, such as voice over, camera angle, and music scores
Such storytelling, by its very nature, gains various outputs:
discussion and consideration
decision and acting
replication or retelling
identity with teller or characters
In my versions of the Nursery Rhymes that follow, I have messed with the interpretations, just for fun. Of course, no actual animal or person has been harmed in the transitions.
A Black Sheep
Abstract: Most sheep are white, but this one was not and he (or she, we can’t be sure) was quite special and clever. I am assuming that it is not racist to refer to a sheep as black and, as the story will show, black sheep were extremely smart and generally in charge of the white sheep. I will refer to the main character of the story as Blackie—again intending nothing sinister or bad. Black is simply the darkest achromatic visual value, although it can have social values as well. For example, if you are “in the black” it is much better than being “in the red”. In addition, the Ovis or Ovis aries clan of sheep have been known to control the wool trade, including dying, shrinking and other complex jobs, for a long time.
Key words: sheep, Ovis, Ovis aries, wool, cotton, bag, baa, sir
Baa, Baa, black sheep
Have you any wool?
Yes sir, yes sir,
Three bags full;
One for the master,
And one for the dame,
And one for the little boy w
Who lives down the lane.
Some background of the story: Wool products were hard to get in the old days, that is, prior to 1733, so selling wool was a very good job to have. There is, however, a lot more to the story and my account will help to fill it out.
There were numerous merchants in those days trying to buy wool—they were known as Wooleys. When one of them would see a black sheep, it would immediately yell “baa, baa” because it thought that the words sounding like sheep language. And it was true that white sheep will stand around all day in the pasture saying just those two words.
In this case Wooley, wanting to get Blackie’s attention, yelled out “baa, baa,” thinking that the black sheep would yell “baa, baa” back and that they could then talk about wool and wool prices in Australia and New Zealand.
But black sheep are different, so Blackie did not say “baa, baa” back to Wooley. Instead it said “Yes sir”, twice, for emphasis, and Wooly loved what he heard because he loved to be called “sir.” In fact, he wanted to be called sir and would often say to the white sheep, “Stop saying baa, baa all the time and call me sir!” But the white sheep could not understand him, for he had never properly learned sheep language. Nor could they bring themselves to teach Wooley the language.
Blackie knew of course that Wooley wanted wool and he guessed that three bags full would be enough. So, he told him he had three bags for him and then he probably went too far—he stipulated who the bags were for. He said, paraphrased, “Wooley, you’re the big shot, the master, so you can have one bag, and your wife—the dame—she can have the other, but don’t forget that poor little boy that lives down the road, actually a small road, just a lane.”
Blackie should not have told Wooley who the wool was for. It upset Wooley because it made him feel selfish taking the first bag. And even though he would give his dame the second bag, he was not going to give that boy down the road any wool. Oh, he might have given him a sack full of cotton, but surely not a full bag of wool.
“Who do you think you are, telling me who to give the wool to?” said Wooley. “I have been buying wool for a long time and I should know who gets the wool and who doesn’t. My wife—OK—she will knit me a sweater, but that boy who lives down the lane throws berries at my horse and I wouldn’t give him a bag of wool. Like I said, maybe a sack of cotton, but not a bag of wool.”
This bothered Blackie, who had started out poor and on the other side of the lane himself. With luck and perseverance, he had become a wool seller. He wanted that little boy down the lane to have the same chance he had in life, so he said once again, “and one for the little boy who lives down the lane.”
Wooley was mad—sellers are not supposed to tell buyers what to do with their money or products. He decided, according to legend, never to buy wool from Blackie again.
Blackie was not discouraged at all. He got to know the little boy down the lane and together they built a large wool shed and decided to pull the wool over Wooley’s eyes. They took three bags of cotton and waited along the road for Wooley to come looking for wool to buy. Remember that cotton was a lot cheaper than wool and if they could sell it at the same price as wool, they would make a lot of money.
And for the next few years that is what they did. How could they manage? Well, by then Wooley had so much wool over his eyes that he couldn’t tell cotton from wool, especially when it was packaged in wool bags. Without meaning to, he had helped Blackie and the boy down the lane become exporters of wool all over the world.
The moral of the story: Children should never say “baa, baa” to someone who might reply “yes sir.” And they should always examine their wool to make sure that it is not cotton.
 See, for example, my analysis of the classification of Kewa stories: “Two Kewa (Papua New Guinea) Story Genres” in Language & Linguistics in Melanesia 35:152-176, 2017.
 My main source has been: Best Loved Nursery Rhymes and Sons: including Mother Goose selections, with helpful guide for parents. Home Library Press, A division of Parents’ Magazine Enterprises, Inc. 1974 edition. There are 251 rhymes and songs in the book.