Just before the AD&D transition from 1e to 2e, several articles appeared in Dragon magazine detailing the "Ecology Of..." various monsters. These reflected the transition of the game itself, moving beyond the simplistic hack-'n'-slash style toward more logical and comprehensive settings, both outdoor and indoor. Published adventuress kept pace, also evolving into more complex and (pardon the term) 'realistic' treatments.
As part of this transition, various monsters initially named for functionality -- such as mind-flayers and carrion crawlers -- were given additional names as being their 'real' or 'racial' titles, sometimes attributed to the races themselves.
Several real-world parallels exist. The Republic of the Union of Myanmar (aka Myanmar) was called Burma for many years until the local name became widely known and used. Various birds are commonly called Wrens, even though their 'true' name (genus) is Troglodytes.
All of these newer and/or alternate names for monsters should be viewed in similar context.
In AD&D, there were dual-wielding rules in 1e (1977) but they were not specifically identified with rangers. A high Dexterity did mitigate the associated penalties, however, meaning that characters otherwise concentrating on a high Dexterity, like rangers and rogues, were natural fits for the style. In 2e (1989), rangers got the class ability to avoid the usual -2/-4 dual wielding penalties.
Aragorn, one of the major fictional inspirations for the ranger, did double wield at least once in the Lord of the Rings (at Weathertop), but it wasn't a major part of his deal. Many other historical figures dual wielded including Davy Crockett and other pioneers that commonly fought Indian style with tomahawk and knife, which has some clear ranger analogues. I remember being inspired re: dual wielding by Madmartigan in Willow (1988) but that's too late to drive the 2e rules.
Much of the shift seems to be game mechanic driven. Not being as armored or as hard-hitting as the fighter, the ranger needed something to boost them mechanically, and dual wielding was chosen due to the alignment with high-Dex.
But What About The Drizzle?
Those who weren't around at the time seem to think that this ranger ability stemmed from the fictional exploits of Drizzt Do'Urden in several Forgotten Realms novels. Drizzt the famous double wielding drow ranger was published in 1988 after being made up on the spot in 1987, really too late to affect the course of the 2e rules. Besides, in 1e drow could (debatably in some circles) double wield; his ability to do so is this more about his drow-itude than being a ranger. Not that he was much of a ranger either, his character sheet on wizards.com says Ftr10/Bbn1/Rgr5.
David "Zeb" Cook, designer of 2e, said when asked where the two-weapon ranger came from,
I'm not sure where the ranger took shape, though I know it wasn't an
imposition because of Drizzt. (Frankly, I've never read more than bits
of the Drizzt series.) It was more to make them distinct and it fit
with the style and image.
Best Answer
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.
A nature spirit that lives within trees
Chwingas have a feature called Natural Shelter that allows them to live within trees and other natural features.
No shared language with humans
Chwingas have no language with which to communicate. The sounds typically attributed to kodama are echoing natural sounds, rather than speech.
Occasional fascination with humans
Kodama are known to take on the appearance of humans, and stories exist of them even falling in love with humans.
Rarely seen
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.
Depicted in media as a tiny humanoid with a white, mask-like face
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: