Daniel L. Everett, professor of phonetics and phonology at the University of Manchester in England, spent seven years with the Pirahã (pronounced pee-ra-HA), a hunter-gatherer tribe of 200 who live in groups of 10 or 20 along the Maici River in the Lowland Amazon area of Brazil. These people call themselves Hiaitiihi: those who stand straight. Everett studied their culture and language--and stumbled on an oddity: the Pirah have no numbers or clear words for quantities, have no differentiated words for familial relationships, and only a few to describe time. They do not read or write, do not talk about abstract subjects, do not use complex sentences and do not learn Portuguese, even though they are in constant contact with the outside world.