1. Mandarin Chinese: Over 1.1 billion speakers
2. Hindi: Over 600 million speakers
3. English: Over 370 million speakers
4. Spanish: Over 540 million speakers
5. Arabic: Over 370 million speakers
6. Bengali: Over 265 million speakers
7. Portuguese: Over 250 million speakers
8. Russian: Over 250 million speakers
9. Japanese: Over 125 million speakers
10. German: Over 130 million speakers
Note: These numbers can vary slightly depending on the source and how "native speaker" is defined.