The Others are a non-human sentient species, which present the greatest threat to the continued existence of humans and the Bobs. They are stated to be socially organized like insects. They invade solar systems and harvest all metal, shipping it back to their home system. They do not care if they destroy other life, even intelligent life, in the process, as they regard other species as "food" or "pests".
The Others know one human language, Mandarin, after capturing and presumably dismantling a Chinese AMI probe. Bob has not learned how The Others communicate among themselves.