The sole official language is Indonesian, known as Bahasa Indonesia. It's based on the dialect of Malay spoken in the Riau Islands and Malay speakers will pick it up very quickly, the main differences being in loanwords — Indonesian borrowed from Arabic, Dutch, Sanskrit, while Malay's loans are mostly from English.

Written phonetically with the Latin alphabet and with a fairly logical grammar, Indonesian is generally regarded as one of the easiest languages to learn, and A.M. Almatsier's The Easy Way to Master the Indonesian Language, a 200 page small paperback, is an excellent starting point. It can be found in any Indonesian bookstore for less than 3 dollars.

The language went through a series of spelling reforms in the 1950s and 60s to smoothe over differences with Malay and expunge its Dutch roots. Although the reforms are long complete, you may still see old signs with dj for j, j for y, or oe for u.

Many educated Indonesians understand and are able to speak English. While Indonesian is the lingua franca throughout the archipelago, there are thousands of local languages as well, and if you really get off the beaten track you may have to learn them as well.

Most educated seniors (65 years/older) in Indonesia understand Dutch.

Educated Indonesians who graduated from Islamic Religious Institutes/Islamic Universities understand and are able to speak Arabic.

English language TV channels are available on most hotels. MetroTV (local TV channel) broadcasts news in Chinese from Monday to Friday at 07.00 AM. MetroTV also broacasts news in English from Monday to Friday at 07.30 AM. TVRI (state owned TV station) broadcasts news in English from Monday to Friday at 04.30 PM in the afternoon. All schedules are in Waktu Indonesia Barat (WIB).