Language in Java
Talk While Indonesian (Bahasa Indonesia) is the lingua franca understood by almost everyone, the majority of Java's population also speak Javanese, a related but mutually unintelligible language. As the largest single language in Indonesia, Javanese influence on Indonesian has been quite significant, in Central and East Java local pronunciation changes — changes include a turning into o, so eg. Surabaya becomes Suroboyo. Other significant local languages include Sundanese, spoken in West Java, Betawi in Jakarta and Madurese, spoken on and around the island of Madura. At the border of the West Java and Central Java provinces, the people use a combination of Sundanese and Javanese which confuses people who speak only one of those languages.
Source: Wikivoyage · CC BY-SA 4.0. Text may be shortened for this guide.