“The History and Outlook of ‘The Origin’ of Japanese Language: How the Origin of Japanese Language has been Debated” (Toshiki Osada edition) (Sanseidō) is written.
Shigehisa Karimata: Chapter 9 How has been the origin of the Ryukyu languages stated - Inquiring the relationship between the Ryukyu language and the Kyushu dialect-, pp. 227-249
Naruya Saitou: Chapter 10 Comparison of genomic and linguistic data, pp. 253-267
Shinjiro Kazama: Chapter 11 Which language is Ainu language similar to? -A trial of contrasting grammar-, pp. 269-313
For the details of the book -> こちら