While theft does occasionally occur, it is not uncommon to see a business man sleeping on the side of Nishizato Street, his head on his wallet. So long as travelers aren't foolish, there shouldn't be any problems here. Travelers are more at risk in their rental cars, as people pull out into traffic with little warning, than anything else on the islands.
talk
While most of the people in Miyako are friendly, Japanese is the main language, followed by the local hogen, or local dialects of each individual town as well as island. While finding English speakers is possible, consider it rare.