The people called "Lusitani" by the Romans were (probably) a group of tribes that came into the Iberian Peninsula. Their language was Indo-European, so it seems logical to consider that they were Indo-European and close similar to Celts. They also had close relationships with Celt tribes.

Lusitanian language has real similarities with Celt-Italian languages. But where did these peoples separated themselves is a mystery yet. The theory of Alps' origin has been related many times. Some investigators talk about south of Russia as origin and place of dispersion of all Indo-Europeans.