Where did English come from? - Claire Bowern
There are two other TED-Ed lessons related to this topic: How languages evolve and How did English evolve? (a lesson that fills in some of the details that we omit here due to the fact that the focus of this lesson was further in the past). There is still a great deal of debate about Indo-European, most importantly about the location of the homeland. To read more about this debate, there are classic books by Mallory and Renfrew, as well more recent works by Anthony. Then, read these articles by Bouckaert et al. At the same site, watch this movie that shows one hypothesis about how Indo-European languages expanded. To learn more about the distribution of languages across the world, see LL-map or The Ethnologue.
Related: Around the world