Thanks for translating this manga. Thankfully, it's funny, cute, short and sweet. The author has a real challenge ahead. I'm looking forward to seeing how this unfolds.
It's hard for young people to navigate Okinawa identity. Unlike most innocent boys from Tokyo, kids in Okinawa aren't born Tokyo-Japanese: they're born into a cross-cultural struggle. For this boy, his love interest speaks a difficult Japanese dialect.
@Kurausukun, for Okinawa locals and linguists, these Ryukyu Islands are home to six or so local endangered languages distinct from Japanese (Yonaguni, Ishigaki, Miyako, Shuri, Nago, & Amami). The differences are not just accents, emphases, or a few words; these languages are not mutually intelligible. The oldest lingua franca in Okinawa might have been Shuri or Chinese, but now it's Japanese.
These local languages are a reminder that the Ryukyu Islands' kings had to fight to unite the islands' diverse residents under one government, creating a multilingual kingdom. That these languages are called Japanese or Japonic dialects results from Japan's colonial period. As is often said, "a language is a dialect with an army." Leaders in Tokyo, Kyoto, and Kanagawa decided the Ryukyu Kingdom could be a Japanese asset, and conquered the islands, first in 1609, and then completely in 1872. The United States even took a turn, after WW2, with the U.S. military governing the islands from 1946-1972. Decades of mistreatment and Japan's Peace Constitution made locals riot, thinking reverting to Japan would make the American bases close - it didn't.
Growing up in Okinawa means choosing an identity, if you can. You can try to emulate Tokyo, but your skin might by too dark to pull off Yamato Nadeshiko or the look of a manga protagonist. It's not fun to aim for almost Japanese. You can aim for gyaru and join the Japanese counterculture, but the roots are different, so grounding yourself might mean at least trying to learn your ancestral language, like Kana in this manga. You can try, like the love interest in this manga, to embrace your heritage, but people who don't know your language won't understand you (that's the vast majority of people).
As you can see, I disagree with the term "dialect" as applied here. It reiterates a colonial understanding, but it reflects important realities. From a Tokyo boy's perspective, probably all of these variations on Japanese are dialects. Even some Japanese scholars, Hiroshi Honma, for example, have written that "Okinawa has always been part of Japan" but that's only true in the sense that Hawaii has always been part of America, or Scotland has always been British. The conquerors replaced their native names, so technically it's simultaneously correct and deeply misleading.
There's another reality it represents too: like the characters in this manga, Okinawa residents typically pepper their Japanese with Ryukyu words and phrases as a kind of compromise, so young people and non-Okinawans will understand. Add to that the reluctance of schools and some local parents to teach their ancestral languages, because it's not necessarily a career asset. In doing so, some residents treat their languages like dialects, so it's natural for someone visiting to think "this is a difficult dialect" not, "why didn't I study French before visiting France?"