* Native speakers: This is the most common metric. By this measure, Hindi is often considered the 4th most popular language after Mandarin, English, and Spanish.
* Total speakers: If we include second language speakers, English would likely remain in the top spot, with Mandarin likely taking the second spot. Hindi and Spanish would likely be fighting for the third and fourth spots depending on the data source.
* Internet users: By this measure, English would be the most popular, followed by Mandarin, Spanish, and likely Arabic in fourth place.
Therefore, the answer to your question depends on the criteria used to define "popularity."