Hi Ash - Thanks for the kindly comments!
You Asked: accents would not correlate to any found in the USA – or anyplace else.
To understand languages and accents on Athera, you really have to look at how the world evolved, and how the population settled in sanctuary.
The dragons spoke Drakish, which had no written form, only pictorial symbols.
Paravians brought the language with them, and it has two forms: the Actualized, which carries AND imprints the flow of prime power, and the everyday spoken form, which "reflects" the flow of power from speaker to listener, but does not invoke actualized creation.
The Fellowship Sorcerers use Paravian, among themselves, and have, since their arrival, though they have knowledge of other languages from their prior experience.
When mankind took refuge, they brought language with them. One common tongue, used today among men, has "split" off into accents, through usage. The older form, held by the forest clans, has stayed mostly untouched, due to their isolation and their strong adherence to tradition. The slight shift in accents would be regional, but as a whole, they have a crisper diction.
The accents in the towns carry the most regional variation. These can be quite distinct. Shand, East Halla, Araethura, Carithwyr, and Korias all have regional variations - the lack of connectivity, the dearth of roads, and the movement of trade leaves some areas isolated from rapid change, and these areas would devolve into accents.
There are three 'dialects' alive - these are amalgamations of the language brought in, colored by ethnic roots. These peoples had their own language, and in the dialects, bits still survive. You have seen the Sanpashir desertfolk, and the shepherds of Vastmark already - with dialect mentioned. Those words are not in usage among any other of Athera's popluation.
The last area where dialect is still spoken is at Ettinmere Settlement, but the story has not yet taken you there. That unfoldment is still to come.
Your last – does it matter where in the series you start? No. I have tried carefully to make a path of entry into each volume - though the notable exception was Warhost, which was "split" off after the finished book.
It remains to be seen if I can make Stormed Fortress a new entry point as well - I don't want to stall the action much at this point, since this is finale, Arc III.
If you started with Fugitive Prince, all the pieces ARE there - but the 'viewpoint' at this state is highly colored…people have tried to begin here, and just HATED Arithon because the foundational events that set him down at this jointure are NOT SHOWN - you only see the impacts on other character's views, and many of them are misguided…nor are the signposts in place, yet, as to which of those views you might trust.
I had one reader say "how much they loved Mearn, he seemed so forthright and true, but WHY was he such a dummy, persistently caring for Arithon?"
If you made entry from Fugitive Prince, I might venture to say you are one who sees VERY clearly, and reserves judgment on others…or you might not have had patience to unwind the riddle of Arithon's past acts with such sympathy.
Brava to you - in my opinion, the world needs more such eyes!
and you're welcome.