During the Alliance era, the Southern Reaches produced many new technologies in use by the Alliance. While most manufacturing was done either off-world or in Modia, several major tech corporations were headquartered in the Southern Reaches, along with many large and prosperous cities.
Then came the Long Night.
While much of the actual resistance in the region was carried out on the Agras and Lowland Plains, the Southern Reaches manufactured powerful weapons, designed by the best inventors at each business. This, in turn, led the armies of Samuel Fate to raze the major cities in the region. During the Sunset of the Long Night, the population centers were obliterated.
The remaining population was put to work erasing all evidence of their once mighty cities, then "geared down" to an agrarian civilization. This was especially challenging as, without modern technology, the region was unfarmable. To further complicate matters, Fate banned reading and writing.
By the True Night phase, the population had been reduced by ninety percent, and any semblance of resistance ground to dust. While Fate stationed governors in the region, they exerted little influence outside provincial capitols, and the now mostly nomadic population was given a greater freedom than those on the Agras, with the provision that they never go near the old cities.
Exactly how Acola began is the subject of folk tales, but most experts agree it was invented around A.D. 1000, originally as a secret code. A common folktale tells, the disparate tribes devised a simple set of code words to determine which tribes still believed in the return of the Dragon (the Battle of the New Day), and which tribes were illegally trespassing on the old city ruins.
The language was created, slowly, from oral tradition. Speakers would use certain passages from widely repeated folk tales to refer to certain concepts (similar in some ways to the Rowen dialect, though much more complex). A speaker might refer to a certain 'mythical' character (such as Hunter Jusenkyou or Jason Bur'I), and some event from their stories would be instantly recognizable.
The language (and variants) were quickly adopted by the nomadic peoples of the region, to differentiate themselves from the settled groups (who still spoke the common language), further weakening their control. The nomads developed an entire culture of their own, and ways to survive in a harsh, resource-poor region.
As the language evolved, the original folk stories were forgotten, and the metaphors and events shortened to make speaking easier. The vocabulary dwindled, but became easier to understand. With only twenty to forty thousand unique words. Still, very complex concepts could easily be communicated with enough words. A common trait was the repetition of a single syllable over and over again in order to indicate intensity.
The simplicity of the language allowed the speakers from any tribe to communicate, allowing for a common culture outside the capitols.
Many tribes independently developed their own writing systems, often in code. The most common original writing system was a rope code of bundles of strings with knots. The number of knots indicated the number of times a syllable was repeated, and their styles represented the syllables. The holder of the bundle had to memorize the syllables, to decipher the message.
The first real writing system emerged around A.D. 2000, and involved a large ball of twine made from leather. Specific items, such as shells or types of rocks, bits of horse hair, animal teeth, feathers, etc., were tied into the twine, followed by knots. The items indicated the syllable, and the number of knots indicated how many times it was repeated. The system was impossible to decipher without an innate understanding of the nomadic culture. An item as simple as a duck feather split in half could mean something very complex indeed.
This system progressed to inscriptions in stone, wherein a pictograph would be scratched on a rock, and a number of notches placed above it. Later additions added notches below. Since the writing escaped the notice of the provincial governors, it was further simplified to a few dozen. Acola translated easily into a language for the blind, who could easily recognize distinct shapes. The sign form of the language was also simple enough that nearly every tribesman learned this as well.
By A.D. 3,000, the Acola had solidified into the modern form. By this time, the provincial governors were aware of its existence and made efforts to stamp it out, to no avail.
Paper had come into wide use. The written language, using a 40-character pictographic alphabet and the notches above and below, allowed for vast and complex literature. While the nomads did not have much use for math or science, they valued history as well as stories and legends, mostly of events before the Long Night.
The Long Night ended in A.D. 3,115, before any widespread action could be taken to stamp out Acola. Many nomadic tribes were quick to resettle the old cities (whose locations had been carefully guarded) and build a new nation around their heritage and language.
Of course, the old provincial capitols still existed, grown into prosperous cities in their own rights. Many other Acola speakers chose to maintain their nomadic traditions.
Acola continued a thriving language into the New Day. Its simplicity made it easier for outsiders to pick up, allowing others to appreciate the rich literary traditions of the unique culture.
In N.D. 500, Acola has billions of native speakers.