Lonely Planet: The world's leading travel guide publisher Indonesian, or Bahasa Indonesia as it's known to the locals, is the official language of the Republic of Indonesia. Indonesian, and its closest relative Malay, both developed from Old Malay, an Austronesian language spoken in the kingdom of Srivijaya on the island of Sumatra. Get More From Your Trip with Easy-to-Find Phrases for Every Travel Situation Lonely Planet...