The series ends with Robin Lustig asking if you can have too much English. From India he hears how English can divide people as powerfully as it brings them together. In the US he meets speakers of Native American languages who want to keep their linguistic traditions alive. And in East Africa Robin asks whether a requirement to speak good English prevents millions from accessing the best jobs and universities.

Some see English as a 'killer language' which threatens the existence of less widely-spoken languages. But not everyone sees English as a linguistic thug. To a Shanghai entrepreneur, it is the glue in the global economy, for others a ladder of opportunity, while some claim English may soon be in retreat.

In an age of linguistic giants including Spanish, Mandarin and Arabic, Robin concludes by looking to the future to ask whether English will continue to dominate or decline, diminish lives and cultures or enrich them.

Producer: Mohini Patel

(Photo: Navajo family attend the Denver March Powwow 2017. Credit: Joe Amon/Getty Images)