The Lusitanians (or Lusitani in Latin) were a tribe living in the west of the Iberian Peninsula long before it became the Roman province of Lusitania (most of modern Portugal, Extremadura and a small part of the province of Salamanca). They spoke the Lusitanian language, an Indo-European language which might have been heavily influenced by Celtic or was closely retated to Celtic, if not a form of archaic Celtic or proto Celtic. Modern Portuguese people see the Lusitanians as their ancestors. The most notable Lusitanian was Viriathus.
Read more about Lusitanians: Origins, Culture, Religion, Language, Tribes, War With The Romans and Eventual Romanisation, Contemporary Meaning