Tracing missing persons can take much patient detective work. But a special kind of "private eye" can trace the missing ancestors of whole (1) peoples by studying the clues buried by words. These philologists, (2) such as the language detectives are called, have traced the word trail (3) back from peoples in Europe, India, South Africa, the Americas, and the (4) Pacific islands in a tiny nameless, and forgotten tribe that roamed central (5) Eurasia 5,000 to 6,000 years ago, before the dawn of writing history. (6) Since a long time scholars puzzled over the striking difference of (7) words in different languages. In Dutch, vader; in Latin, pater; in old Irish, athir; in Persian, pidar; in the Sanskrit of distant India, itr. These words all sounded likely and meant the same thing-"father". Where did it (8) happen that widely separated peoples used such close related sound symbols The problem baffled linguists for years. The more so because (9) "father" was but one of a host of such coincidences. Towards the end (10) of the 18th century it dawned on scholars that perhaps all these words stemmed from some common language.