The World: History
In order to understand the modern-day setting and therefore the setting of the fanfics here, it might help to go back a bit and explain its history.
For the sake of making this simpler and getting to the point, I've excluded the mythology of the Pokémon world -- namely, the function of legendary Pokémon. This usually varies by region or religion anyway. For example, the people of Johto follow the idea that Ho-oh is the judge of Heaven, the god of the sun and reincarnation, whereas the people of Sinnoh recognize Giratina as a guide to the afterlife. Even more radically, the people in England have what's mostly a Christian-based religion, whereas the people of Japan follow something more Buddhist-like. (Note: I say "based" and "like" because they're not actually the same religions as their real-world equivalents. Usually, they involve the worship of legendary Pokémon. It's just that these religions tend to have traditions and prayers that mirror those of real-world followings.)
That said, throughout human history in the Pokémon world, things have been similar but not entirely the same thanks to Pokémon. At one point, far back in ancient times and at the beginning of the domestication of both Pokémon and animals, humans saw Pokémon as equals. This was called the Pact, and it basically ensured peace on the planet. Pokémon ate at the same tables as humans, helped humans wherever they could, and sometimes even fell in love with humans -- and, well, vice-versa. This lasted for thousands of years until humans became more civilized.
As this happened, humans began to see themselves as the dominant race to most Pokémon except the legendaries. Hence, the Pact was broken, and most Pokémon retreated into wild areas until they were caught and tamed by humans. Even then, keeping Pokémon was often a dangerous and difficult task due to the fact that most Pokémon avoided domesticity as much as possible (except for those that were bred in captivity, such as Miltank and Mareep after the introduction of agriculture) until humans learned to make strange devices from Apricorn seeds and other magical items. (See Pokémopolis.) These objects, which operated through a means not fully understood even today, had the ability to convert Pokémon into forms of energy and store them for long periods of time. Pokémon who underwent the conversion process (i.e., were captured) had a tendency to be friendlier to humans in general or were more open to forming a relationship with human partners.
Hence, Pokémon training began as a means of taming Pokémon for survival purposes. The first to be tamed were Pokémon that could be used as food (Miltank, Farfetch'd, and Cherubi, to name a few), the production of other necessary goods (Mareep for wool, a number of Water-types for water), or the herding of lesser animals (Growlithe to help herd cows and sheep). In other words, Pokémon once again became partners to humans, but they were not, at this point, equals.
As humans evolved from primitive cultures to more civilized people, wars over goods and territory began to break out, and humans learned how to use Pokémon for battling as a direct result of the need for a powerful military force. Pokémon were specifically taught how to fight for humans because numbers of them were simply a better means of defense than actual weapons. After all, a Flamethrower from a Charizard was always more effective at repelling invaders from a castle than bows and arrows. Thus, although humans developed weaponry, it was never as advanced or necessary compared to Pokémon until modern times, when wars began to become more violent (and laws against killing Pokémon were put into place).
Likewise, at around this time, Pokémon training for recreation began. These were the Middle Ages, and it was a form of keeping Pokémon in shape while entertaining the court. Such practices were thought to have originated in Japan, where the oldest Pokémon Leagues are still in existence.
Japan itself has been pretty much a picture of a feudal society up until a few decades ago. The nation had been ruled by an emperor (who is more of a figurehead today), samurai held large swatches of land, and the culture was heavily what one would think of as ancient Japanese. They worshipped Pokémon, and in some cases, they established large shrines dedicated to them. (This is notably true in Johto, where many of these shrines -- including one burnt down by mysterious means -- are now tourist spots.) Naturally, Japan was not the only area that was in isolation. Every nation had its own culture and its own language, and there were political, cultural, linguistic, and religious barriers that were deeply respected, much like there are in the real world.
However, this all changed roughly one hundred years ago. War began to break out in various parts of the world over things that weren't entirely clear. Japan itself didn't entirely get involved until the middle of this long series of events, when the emperor before the current one attempted to take advantage of the weakening world to expand the Japanese empire. After that point, things escalated.
There were over four different wars fought during the period known as the Bloody Ages. Europe was torn apart and reassembled several times. Asia experienced several genocides. Africa suffered a plummet in population as it fought its own internal wars. Even the Americas suffered, particularly the United States.
In the last war, the human population was essentially decimated. After it finally and abruptly died down, all nations sat in a mess of broken economies and annihilated infrastructures until several world leaders met to hammer out a peace treaty. As a result, barriers were loosened, trade was established, and the human race began taking steps towards unification and advancement as one people.
This isn't to say that there weren't problems after that point. The state of the US only got worse, and certain vibrant cities such as Hollywood became dilapidated ghost towns. Meanwhile, the remaining populations tried to form newer towns away from the memory of what the US was. Wars still popped up, particularly in the Middle East and Africa. (One of which Americans such as Lt. Surge saw active duty.) Unfortunately, the treaty only favored those who accepted it, and even then, it focused itself on its strongest countries -- which were usually located in Europe and eastern Asia, not the Americas or anything else. It was inherently flawed, and outside of the nations protected by the treaty, there are still groups of those who object to it today. (Many others wish to benefit from it and attempt to work towards being recognized by it.)
Meanwhile, Western culture dispersed throughout the globe thanks to the unification movement. With the US and parts of Europe struggling to repair themselves, waves of immigrants migrated to more prosperous areas, particularly Japan. These waves made it necessary to develop a common language -- literally called Common, an off-shoot of English. Additionally, formerly culturally heavy nations such as Japan began adopting Western culture as the Japanese natives, perhaps repentant for what they tried to do during the middle of the Bloody Ages, were unusually receptive to the foreigners. Soon, it didn't become unusual for children to be born with Western names and elements of Western culture. Hence, the end result was that at the end of the twentieth century and the beginning of the twenty-first, Japan became a heavily Westernized civilization thanks to the treaties formed only a decade or two ago.
It should also be noted that "modern day" (the time of Ash Ketchum's journey) really is roughly present day according to the real-world timeline. (Specifically, in AEM, the year is 2002, with the assumption that Ash initially left Pallet Town in 1997.) Technology has always advanced more than it has in the real world, and thanks to the advanced science of the ancient past, the human race has been able to develop beyond MP3 players and hybrid cars to invent things like highly advanced AIs and teleportation devices.
Because of the identity of the casts of my fics, special note needs to be made about the latter. Back in the late 80's and early 90's, Dr. Akihabara of Kanto developed a system that was able to transport Poké Balls from one point to another. The first of these systems were used by Nurse Joy to transport Pokémon from one center to another in emergencies, but when it was seen how useful the system was, trainers and other occupations began using it as a means of convenience.
However, Akihabara's Transport System had one serious flaw: the fact that Pokémon were stored physically. That is, the Transport System was essentially a sending pod and a receiving pod. Someone had to be present at the receiving pod to pick up and store the Poké Ball, and in the case of professors who might be the designated storage point for trainers, this meant that the recipient needed to have large amounts of space and ample time to not only store the Poké Balls but also maintain them and the Pokémon inside them. This was aside from the fact that transportation of large numbers of Pokémon was slow because every Poké Ball could only be received and processed one at a time.
Noticing this problem, kid geniuses Bill McKenzie and Lanette Chastain began working together to develop a means of storing Pokémon in a compact and easy-to-maintain space. Their solution: the computer. It took a few years of modifying the Transport System and coding the proper programs before they managed to create the Pokémon Storage and Retrieval System. The system was tested in Kanto (Bill's region) and Hoenn (Lanette's region), and in a matter of months, trainers found it to be not only stable but also far more convenient than defining a recipient and contacting them to ensure the transfer was successful. Thereafter, the system spread to the rest of Japan and (thanks to Professor Krane of Orre) parts of the US, and plans are currently in production to bring it to the rest of the world. However, even in Japan, the system is relatively new. Not every trainer is given the option to use it when they start out, and Akihabara's Transfer System is still predominantly used. Even so, plans are being made by the Pokémon League to require a switchover to the use of the Storage and Retrieval System within five years.
The introduction of the Storage and Retrieval System was about three years before the start of Ash Ketchum's journey. Currently, my fanfiction assumes that Ash took roughly a year to travel through each individual league, so it's been about five to six years since Ash left Pallet Town.