Basque is a very singular European language that a very little community speaks in northeast of Spain and southwest of France.
In spite of the fact that Basque (Euskara, in its original name) is surrounded by other languages and coexists with them (Spanish and French, principally), nowadays its origin is not clear.
Same theories has been proposed but as far as I know today is not a real agreement about how it managed to survive from the antiquity up to ours days and about what is the relationship with other European languages.
Nevertheless I have just read in Euskal Herria (and wonderful monthly magazine about Basque culture and nature) that a surprising old theory is been powering by means of new evidences that Josu Naberan has showed off.
According to this theory the archaic Basque languish root agglutinated another two languages: Bereber eta the lost language that was spoken in the zone of the Mediterranean
By means of this agglutination Euskera became a very strong language and this fact facilitated the spreading of Euskera along European continent after the after the last glaciation, 12,000 years ago.
The fasts to support this theory are really unexpected. Details about Basque toponimic names in Germany, Morocco, Siberia, Aquitaine and India are the principal source to try to demonstrate this theory.
Who knows. One of the most tiny language was, in other epoch, one of the most strong one.
Anyway, do you know that Basque is the principal language in Ikastorratza? Please read this sort introduction.

Photo credit: Wikipedia.