San Sebastian, Spain - No frontier marks the entrance to Spain's Basque region, but the traveller passing by quaint villages on green hillsides has a clear sense of entering a distinct territory. It is not just the Basque flags here and there. It is, above all, the signs in a strange language unlike any other in the world. A travel bureau, for instance, is marked 'bidaiak.' An ice-cream shop has a sign saying 'izozkiak.' A police station is marked 'ertzainza', and an office of the Basque regional government is called 'eusko jaurlaritza.' Scientists remain puzzled by the Basque people of...