1. Spanish: It is officially spoken in 21 nations.
2. Chinese: Many nations have Chinese communities and learning the language can help you communicate better while travelling.
3. French: Not every local in France speak English. Thus, knowing the language can be a huge perk.
4. Vietnamese: It's hard to find English-speaking locals in Vietnam. Know the language or use Google Translator.
5. German: You'll find it useful in many European countries.
6. Russian: Russians love to travel. You'd find a Russian in almost every destination.
7. Bengali: When you speak with a Bengali in Bengali outside India, be ready to make a new friend already!
8. Hindi: Hindi is one language that even many foreigners understand.
9. English: Worth mentioning, knowing English is mandatory for world travel.
10. Arabic: Travelling to the Middle East? Arabic can help you understand the local culture better.