“On 4 November 1995 Kasabe existed; on 5 November it did not.” This brief
obituary in David Crystal's book (p. 1) does not refer to a creature. It refers to an African
language, known as Luo, that had been spoken in Cameroon; on the day in question, Bogon, the
last speaker of Kasabe, died, taking his language with him. According to Crystal, half of the
world's current languages are in danger of dying, and the situation is so grave that an
international and interdisciplinary effort must be mounted to rescue them. Crystal has written this
book to alert us to the peril and to suggest ways in which our linguistic diversity might be
maintained.