What is the most widely-spoken language in the world? Based on the data presented on The 100 Most Spoken Languages Around the World, which has been sitting in my collection of interesting snippets for a while now, English safely claims that title. However, that changes if you ask about the most common natively-spoken language. English puts in a good showing (thanks USA) but is eclipsed by several others including Mandarin Chinese and, albeit relatively more narrowly, Spanish.
Some languages have almost no non-native speakers, such as Hungarian and Japanese, while others have few or no native speakers (Modern Standard Arabic).
It is a fascinating set of information and an excellent way of displaying it.