In Tomb of Annihilation dnd-5e, the chwinga are described as "small, shy elemental spirits" who are vaguely helpful to the characters if allowed to run their course.
Are chwinga new (in D&D) to 5e, or did they appear in earlier editions? Are they lifted from pre-existing mythology/folklore?
I don't have a primary source to confirm this, but I'd be very surprised if the chwinga wasn't based at least in part on the kodama.
Chwingas have a feature called Natural Shelter that allows them to live within trees and other natural features.
Kodama (木霊, 木魂 or 木魅) are spirits in Japanese folklore that inhabit trees, similar to the dryads of Greek mythology.
Chwingas have no language with which to communicate. The sounds typically attributed to kodama are echoing natural sounds, rather than speech.
In some cases, a chwinga might simply like the way a humanoid walks or the way it combs its hair. Other times, it might be smitten by a humanoid's ability to play music or to eat copious amounts of food.
ToA p.217
Kodama are known to take on the appearance of humans, and stories exist of them even falling in love with humans.
Chwingas have numerous abilities with which to make themselves unseen: between Natural Shelter, pass without trace, and +7 Stealth, they aren't seen unless they want to be.
Similarly, kodama are rarely seen, to the extent that a tree in which one lives is referred to as a kodama as well.
ToA describes chwingas as appearing like animated dolls, and minus the black skin and hair, in the illustration they bear a striking resemblance to the kodama in Princess Mononoke:
Chwinga are based on the Mmoatia, who are forest fairies of Medieval Ghana and Ashanti mythology.
Mmoatia (singular, Aboatia), are said to be forest dwellers of Ghana. A subclass of Abosom (intermediary spirits, or the enlightened dead). They are believed to be very short in stature, standing not more than one foot high. They have curved noses and yellowish skin. Their feet point backwards.
These beings communicate with each other through a unique whistle language, and whistling in the bush is a sure way to draw their attention.
They are credited with a phenomenal knowledge of medicines, which they are willing to impart to herbalists or medicine men. Sometimes Ghanaians are taken by Mmoatia that live deep in the woods. Some who are captured by the Mmoatia begin to learn their ways and emerge after several years as herbalists. The Mmoatia have always lived in the jungle and know how to use its plentiful resources to cure to all diseases. Their favorite food is bananas.
Mmoatia are divided into three tribes or bands: Black Mmoatia are harmless, but Red and White Mmoatia are always up to some kind of trickery, though they are not truly malevolent. Mmoatia signify unpredictability, mockery, and trickery. They function as messengers between the realms of spirit and corporeality.
The chwinga are a new invention of D&D 5th edition. They don't appear in earlier editions of D&D, and I can't find any creature by that name at Google Books or the Internet Archive's library. The creature's inspiration would be a matter of speculation; we might not be certain without asking the book's designers.
However, I did find the term chwinga in some old texts, where it refers to an item or concept in Australian aboriginal beliefs.
Encyclopedia Britannica Vol.19 says:
The sacred as the secret. The literal sense of the term chwinga, applied by the Central Australians to their sacred objects, and likewise used more abstractly to denote mystic power, as when a man is said to be “full of churinga,” is “secret,” and is symptomatic of the esotericism that is a striking mark of Australian, and indeed of all primitive, religion, with its insistence on initiation, its exclusion of women, and its strictly enforced reticence concerning traditional lore and proceedings.
The Native Tribes of Central Australia mentions chwinga or "churinga" as part of the beliefs of the Arunta or Arrernte people. A churinga is a sacred object or totem, though the word itself may also mean "sacred". Lectures On The Religion Of The Semites The Fundamental Institutions (1927), p. 568 and 635, describe churinga as sacred stones.
Wikipedia has an article on these sacred objects, spelled also tjurunga. The article describes that magical powers might be attributed to tjurunga, and that they are held with such secrecy that only certain people are allowed to view it.
D&D's chwinga can turn into long, thin stones when they die; have a connection to stone, grant benefits to humans, are highly secretive, and are often depicted as dark-skinned. In that regard, they resemble the sacred stones of Arrernte belief. However, they may also draw from other myths: melding into stone is a trait of dwarves from Norse myth, being secretive and giving gifts to humans are traits shared with the Japanese korobokuru, and the notion of little men who use magic and live in the woods appears in English folklore.
