Complex sentence: Large Berber-speaking migrant communities, numbering today about 4 million, have been living in Western Europe, spanning over three generations since the 1950s and about half of them were born in Europe.
Split into simpler sentences: Large Berber-speaking migrant communities, numbering today about 4 million, have been living in Western Europe, spanning over three generations, since the 1950s. And about half of them were born in Europe.