1. Mandarin Chinese: 939 million
2. Hindi: 602 million
3. English: 379 million
4. Spanish: 534 million
5. Arabic: 274 million
6. Bengali: 265 million
7. Portuguese: 258 million
8. Russian: 154 million
9. Japanese: 128 million
10. German: 78 million
Note: This list only accounts for native speakers. If we consider second language speakers, English would likely rank higher.
It's important to note that language statistics can be complex and vary depending on the source and criteria used. These figures are estimates based on various sources.