Random idea based on the obscure pre-roman history of the Iberic Peninsula, and later movements of peoples - the invasion of the muslim forces, ressac and the Sepharades going to Maghreb(?), implying the Columns of Hercules can be crossed easily kinda, and sailing around existed...
Could (or was!) a people of the Berbers familly languages and culture(s) move into Iberia of the distant past (or more recent), and an iberic berber language stay alive or even prosper? Interactions with greeks, the punics, Rome?