Here are a few ideas to get you started!
1. Travel possibilities
2. Widen horizens
3. Career progression opportunities/improve employment potential
4. Learning about your roots
5. Culture - watch English-language films, listen to English-language music etc
6. Languages are a challenge!
7. Understand and appreciate own language and culture better
8. Increase global understanding
9. Make friends from all over the world
10. Think it sounds beautiful/is particularly expressive