Indonesia has around 700 languages. The languages are different in each region, or we call it province. According to wiki, there are around 42,8 million Indonesian native speaker, which I find as odd because Indonesian population is 249 million in 2016. But then it has 154 million second language Indonesian speaker. Then it makes a little bit more sense, because most of Indonesian at least have to understand 2 languages; Indonesian (or bahasa Indonesia) and their respective mother language (and if their father comes from different tribe then they might have to learn their father’s language). Indonesian as the second language, if they considered mother tongue as their first language.
In my case for instance, my parents are Javanese (yes that Java like the coffee, its an island name btw), therefore they speak Javanese at home and thus I learned Javanese passively. I can speak it in normal form but not the polite form. I think like most Asian language there are several levels, per se for each language. The polite form is used when you talk in formal settings or to elder, in Javanese its called Kromo. The normal form is used when people from the same or younger, which is called Ngoko, I can do this one but not Kromo. They have totally different vocabulary. My accent is super weird. Anyway, Javanese is my mother tongue. Its pretty cool that Javanese has more than 80 million native speakers in the world, well I suppose we win by number or its just that there is no better official statistics in other Indonesian local language.
I was born and grew in the West Java near Jakarta, thus the local language is from West Java which slightly have overlapping vocabularies but totally different grammar with Javanese. I learned it since my elementary school until junior high, so it was 9 years total. But I still only able to speak the crude from of Sundanese, to the extent that I can have the accent and tone, and survive when I need to bargain stuff from traditional market (and some bonuses from the seller lolol). I can’t say that I can speak Sundanese fluently lol.
Then Bahasa Indonesia which is our national language. Bahasa Indonesia is a compulsory language that unite these 700 hundred different language speakers. In a way, I think Bahasa Indonesia (the language) to Indonesian is like English to the world, its like the common ground where people in Indonesia can speak to one another despite of the difference of their mother tongue. I am most confident with this one since I used it the most lol. It has around 77 million native speaker, but if you count anyone who can speak Indonesian fluently then the number must have exceed 200 millions. Then for me its my native language.
Then English, its also a compulsory language that is taught from elementary school all the way to university. We know English as a window to know world since its an international language. Western culture is strong in Indonesia I guess.
Japan is my dream-country. I love every aspect of it, including the language. Well, after years of watching anime, listening to Japanese songs, its unavoidable to not knowing some Japanese words lol and I formalized it by learning it in language courses (but anime plays important role in enriching my vocabulary which is a bad idea since it is not usually used in daily conversation. When I stayed in Japan with my friend’s family they told me not to talk in anime manner such as ” Uruha, (thats how they called me) Don’t use ‘Souka souka or sugeee~~’, you sound like an uneducated person” and when they said that I was EMBARRASSED TO THE CORRREEEE). I am not really good at it yet, though hopefully one day I can be fluent in Japanese. I think my level in in beginner that slowly moved to intermediate speaker..totally overconfident
I also learn Arabic, not the grammar but only the letters to read the Quran. I still learn it until now hahah… And oh Indonesian language is written in Roman letters, like usual English without any accents. Javanese was written in sanskrit in the old times, I think it is still taught in Javanese school but not used in daily life. Not sure about the others.
So on my case I can speak Indonesia, English, Javanese, and Japanese (et un peu Francais und Deutsch – to the level where I can only introduce myself). I think any Indonesian can easily speak two languages: their mother tongue and Indonesian at least. They may or may not fluent in English but at least they learned it in some point during school. And Arabic, if they are moslems. I knew a professor in my campus that can easily speak Sundanese, Javanese, Padang-nese (?), Deutsch, English, Indonesia and some other languages fluently. I bet most people in the big cities can speak English well, and in Bali ( for the tourism I guess). Moreover if they add more foreign language such as Japanese, German, and other languages from school. Indonesians are also one of the country with most people speak more than 2 languages. Cool stuff!