What is the origin of the word yummy, as in This food is yummy? All I can find are dates of known first uses.
"delicious," 1899, from baby talk. Yum-yum as an exclamation of pleasure is recorded from 1878.
The American Heritage Dictionary of the English Language says:
From yum, the sound of smacking the lips.
The Collins English Dictionary says:
From yum-yum, of imitative origin.
Origin of YUMMY: yum-yum. First Known Use: 1899.
Everyone seems to agree that this is an onomatopoeia.
There are different hypotheses as to the ultimate origins of yummy, which may be a cognate in countless languages or a borrowing from languages like English.
I don't personally see any phonological principle to the notion that all or most languages spell the sound in so similar a way because it seems to describe the movement of the mouth as it chews (mastication), since if this were true, most onomatopoeiae should also be the same internationally, which is not at all the case and sometimes for what may be thought the most basic of sounds. What's more, as far as I've read, most onomatopoeiae are not borrowed from one language to another.
Prior to introducing a few different hypotheses and observations, I'd also like to say that for the item to be a mere onomatopoeia, it seems noticeably convenient that the word be so similar in sound in so many different languages (some of which are unrelated). Too, for the item to be a mere onomatopoeia, I find it even more convenient that it be so similar in both sound and meaning in each respective language within a given geographical area. For root words like per- and mer- to be the same in so many European languages, one concludes that there must of have been some linguistic influence prior to both that gave way to their presence across so many languages (proto-indo European, of course). Why then do we assume that yum, yummy, or yum-yum is merely an onomatopoeia that appeared in so many different parts of the world with such similarities, unless there is a timeline that best explains such?
To start, I introduce the hypothesis put forward by some linguists that the word comes from the Zande people in Central Africa, [who were called] the Niam-Niam by outsiders around the time of their discovery in the 18th century. This name is probably of Dinka origin, and means great eaters in that language (as well as being an onomatopoeia), supposedly referring to cannibalistic propensities (wiki - although no reference is provided for the claim that it was an onomatopoeia in said language).
An important point should be noted here: On the one hand, for this to be at least partially true as regards the word's etymology, it would seem that the Zande people would have had to be discovered much earlier by the Dinka and in turn the West, since the description of the sound must, at least abductively speaking, predate the 18th century (unless prior to the 1700s food simply wasn't thought of as good or no such phonetic description existed, which hardly seems plausible).
At the same time, with the great scramble into Africa in 1835, not to mention slavery itself, far earlier, it should seem a fine argument indeed that the word be spread into the rest of the world that way. Even in countries and their respective languages as far away as Senegal (when to Sudan and its ethnicities), the word for food is “nyami." In French, phonetic theory could indeed explain miam-miam, which of course just means yummy.
Following this line of thinking, and going thus further back, the Dinka are a very spread-out population who inhabit not just most of South Sudan but also primarily the Nile River and Ethiopia, etc. Why this is relevant is the population is (and for thousands of years has been) too close to Egypt (and therefore ancient Egypt) to leave out the fact of the ancient Egyptian deity, Ammit, as it transcribed into English.
That goddess, the first syllable of which seems too similar to be mere phonetic coincidence, had the head of an alligator (which if you think about it does have an incredibly big mouth), and was a funerary deity, her titles including "Devourer of the Dead" and "Eater of Hearts", among others (no reference should be needed here, but just in case: The Routledge Dictionary of Egyptian Gods and Goddesses, Second Edition). Although this hardly seems convincing, since too much is being speculated here, what might be borne in mind is that said deity may have been as important as words like devil or satan or to eat in our culture, the time and place in which the word occurred far predating science and any conflicting worldviews.
Although it may be irrelevant to add, in Luxor, (Egypt) Ammit is actually called Yum Yum, and the transliteration of Ammit in Arabic is 'umat (dialects aside) from the verb أمت, which is translated as to die (most frequently) and again comes from said deity. To get a broader picture of any possible connection between death and eating, a mere reference on Wiki to Ammit will clear that up in addition to the reference above. Of course, it can't be forgotten that the reason Ammit is so-called in today's Luxor may be mere coincidence or even a putative adaptation. Although phonologically one could attempt otherwise, which only goes to say that more than mere sound, there is a curious corresponding meaning.
A look into a translation of the word across languages (and therein their etymologies) would no doubt help to establish corroboration for the hypothesis that the origin is indeed Egyptian. Ancient Greek in particular and in turn Latin should seem fine candidates to test the hypothesis that Ammit gave way to said interjection in the two languages and possibly thus later European languages, among others.
Should it be found that Greek and Latin have no such record of the word, in Turkish, (the history of the Ottoman empire and its expansion into Africa and Egypt aside) myamyam means cannibal (apparently or perhaps at best a deceptive cognate for the English yummy, yum, or yum-yum, or the French miam-miam, not to mention other latinate languages), and does indeed predate the Dinka's usage by some two hundred years. On this front however, it comes to mind that neither is mutually exclusive. On that note, however, it seems possible that the word was introduced through Turkish into most European languages.
To explore still another good hypothesis, we turn to India, which should seem to hold a very good case for the appearance of yum-yum in English on its side of Europe and the New World as well as parts of Asia, in which it has had such a linguistic impact. In said line of thinking the word yum could be argued as having come from the Sanskrit mantra ‘Yum,’ which is said during meditation. It helps to focus concentration on love and good things. The meditator would repeat Yum, Yum, Yum. Those traveling to India in the 1800s picked up on this (although the site from which I collected this idea provides no evidence for the word's having been "picked up on" and what is implicitly argued for: "spread to England").
One issue that seems to come to mind with this idea is that Indian exports to England started over two hundred years earlier than the 1880 dictionary entry and nearly 200 years earlier than the word's use in recorded English. Additionally, adopting the word yum from the practice of meditation seems a far stretch when to saying that something tastes good when words for such already existed in English. Perhaps if it were used in the right setting it would make more sense.
Whatever the case may be, we can't forget that dictionaries themselves are a rather recent development in the recording of language, and so while it is entirely possible that the word is far older than etymologists in the English-speaking world seem to have let on, it could just as well be that because the word is not just an onomatopoeia but also often used by children, it simply never made it into older extant texts. In other words, perhaps that the 19th century seems to be the time around which it was recorded in English has more to do with the appearance of English dictionaries than the appearance of the word. Notions of language and literature and what (as in morphology) constitutes words have (as notions) changed drastically in the past two hundred years, let alone longer.
I can't offer any informed speculation about the word's etymological origin, but I can point to an instance of the expression from a much earlier date than 1899. The following passage, from William Howard Russell, My Diary: North and South, page 271 (a diary entry dated May 10, 1861), follows a story told by a fellow passenger of Russell's about how their steamboat's captain had underhandedly acquired a cargo of slaves at a time when U.S. law banned the importation of newly captured Africans as slaves into the United States:
It was worth while to see the leer with which he [Captain Maher] listened to this story about himself, " Wall now! you think them niggers I've abord came from Africa : I'll show you. Just come up here, Bully!" A boy of some twelve years of age, stout, fat, nearly naked, came up to us ; his colour was jet black, his wool close as felt, his cheeks were marked with regular parallel sears, and his teeth very white, looked as if they had been filed to a point, his belly was slightly protuberant, and his chest was marked with tracings of tattoo marks.
"What's your name, sir?"
"My name Bully."
"Where were you born?"
"Me born in Sout Karliner, sar!"
"There, you see he wasn't taken from Africa," exclaimed the Captain, knowingly. "I've a lot of these black South Caroliny niggers aboard, havn't I, Bully."
"Are you happy, Bully?"
"Show how you're happy."
Here the boy rubbed his stomach, and grinning with delight, said "Yummy! yummy! plenty belly full."
"That's what I call a real happy feelosophical chap," quoth the captain. "I guess you've got a lot in your country can't pat their stomachs and say, 'yummy, yummy, plenty belly full?'"
In fact, the lad, and a good many of the hands, were the result of Captain Maher's little sail in the Czar [the steamship he had used to transport the illegal cargo of captive Africans].
An excerpt containing this text also appears in "Extracts from "My Diary.' North and South," in the Sydney [New South Wales] Morning Herald (March 9, 1863).
Russell was a correspondent for the Times of London. In this extract he reports the use in 1861 of yummy by a young African-born U.S. slave to indicate his being well fed. The most notable point here is that the usage is earlier than both the 1899 first occurrence date for yummy identified by Merriam-Webster and Etymology Online and the 1878 first occurrence date of yum-yum identified by Etymology Online.
Any persuasive etymological explanation of the emergence of yummy in English will have to account for this 1861/1863 occurrence of the word.