The chart in this article might help you decide what foreign language to learn next: agenda.weforum.org/2015/10/which-languages-are-most-widely-spoken/
But I think it is also interesting to work backwards to notice what languages have the most non-native speakers. English clearly has the most, but French (the former “lingua franca” – to point out the irony of the term) still has the next most, followed by Hindi.
