"One language sets you in a corridor for life.
Two languages open every door along the way."
I myself have been speaking Indonesian as the mother tongue the language of unity. You know Indonesia has more than 400 languages. Our Founding Fathers made the Indonesian language as the language of unity. That's why despite having more than 400 languages, we only speak one language, Indonesian, which has been enriched with a variety of vocabulary (local and foreign languages --Arabic, English, Dutch and another) as the lingua franca*.
However that does not mean we Indonesians are not allowed to learn a foreign language. Amazing! I myself learnt more than three foreign languages (Arabic, English, Dutch and German) since I was at school. How about you, please to share your experiences in language learning.