Inter-disciplinary research bringing together linguists, geneticists, and archeologists is throwing new light on hitherto intractable questions relating to prehistoric human population movements. Four case studies are examined in detail to illustrate such results: (i) the origin of the Haruai people of south-eastern Madang Province, Papua New Guinea; (ii) the arrival of Turkic languages in Azerbaijan; (iii) the Indo-Europeanization of Europe; and (iv) possible scenarios for the arrival of the English language in Great Britain.