>>6351855The reason for this is because of their etymological origins, actually. Arkansas originated from the Algonquins, who called them and their land the Arkansas, which just means "south wind". The issue comes now to what exactly they were called via how they were spelt. The earliest French explorers in the area spelt it as Akansea, which would in French pronunciation, would be pretty close to Ar-kan-saw. Then it was, simplified to Acansa and then the tribe was referred to as Les Akansas by the French again, a half-century later, which we know 100% is pronounced A-kan-saw in French. Then another half century later, an American mapper for the area used his dialect to spell it as Arkansaw. The issue is not that Arkansas' pronunciation was ever wrong to begin with, but due to a disagreement. When Arkansas was being drafted up for formal statehood, there was no agreement between the two senators on to how the state should be called or pronounced. One of them wanted it to be pronounced Ar-KANSAS and spelled Arkansas, while the other wanted it to be Arkansaw and pronounced Ar-kan-saw. The first senator wanted to stay true to the written word despite its pronunciation, but the other senator wanted the spelling to reflect the pronunciation. They reached an agreement to honor both, by having it spelled closely to its roots in Akansas while taking on the pronunciation it always had, irrespective of English language conventions.
>tl;dr: Arkansas uses its historical French-derived pronunciation rather than conventional English pronunciation Kansas, in comparison, is much more straight-forward and better preserved from its naming to conventional day pronunciation.