Ryukyuan languages

The Ryūkyūan languages (Okinawan: 琉球口, "Ruuchuuguchi") are a group of Japonic languages spoken in the Ryūkyū Islands, the southernmost part of Japan. The languages are Amami, Kunigami, Okinawan, Miyako, Yaeyama and Yonaguni.
Although Japan says the Ryukyuan languages are dialects of Japanese, most linguists see them as languages. This is because Japanese speakers would not be able to understand Ryukyuan without learning it.
In the past, the Ryukyuan languages were spoken all over Ryukyu but due to the languages being discriminated against, most Ryukyuans now speak Japanese.
History.
When a group people called the Yayoi came to Japan, they brought over a language called Proto-Japonic. This language diverged into Japanese and Ryukyuan overtime.
Sound Changes.
Japanese and Ryukyuan has different sound changes. For example, Japanese “o” becomes Okinawan “u”. This is why the Japanese word “to” (and) is “tu” in Okinawan.
It’s also common for Japanese “k” to become Okinawan “ch”. This causes “Okinawa” to become “Uchinaa”.
In the Yonaguni language, Japanese “y” becomes “d”. Japanese “yama” (mountain) is “dama” in Yonaguni.
Language Usage.
Most older Ryukyuans can speak a Ryukyuan language, while younger people speak Japanese. Ryukyuan languages are also spoken in Hawaii and South America as many Ryukyuans live there too.