To be completely honest, I lack the personal experience, expertise, and/or eloquence needed to give a satisfactory answer to this question (hence why I work within the bounds of what the lore tells us), so I’ll provide a summary, links to informative threads, and what we can surmise based off of AKATSUKI’s (scant) interactions in Okinawa.

Here's a summary from The Rising Powers Initiative

"Okinawans, formerly known as the Ryukyuans, existed as the Ryukyu Kingdom since the 13th century until Meiji Japan forcefully annexed the island nation. Under the Japanese colonial rule and assimilation policy, the Ryukyuans lost their own culture, language, land, and political institutions."

Here are a few threads that I ...