Scattered All Over the Earth by Yoko Tawada

Japan has vanished, and Hiruko thinks she might be the last Japanese person left. Travelling across Europe with a group of new-found friends - a linguist, a student moving between genders, a Greenlander hiding his nationality, and his broken-hearted lover - she pursues a mysterious man named Susanoo, who may be her last chance to once again hear the sounds of her native tongue.