"Mother tongue" and "native language" are the same thing, but in different registers. "Mother tongue" is part of common, daily speech and "native language" is more academic and abstract. We get this difference from the word-origins. This is also why "mother language" and "native tongue" are understandable but sound a little "off". The words don't naturally go together. "National language" is just that: the language of a nation.

Mother tongue and native tongue mean the same thing, the language that you learn from birth and use to do most of your speaking. Bahasa Indonesia is a Lingua Franca, a language used to communicate by groups of people that speak different native languages.

Mother tongue and native language are synonyms. Mother tongue is rarely used in American English and is more common outside of North America. I think the word you are looking for is dialect. A dialect is a form of a language which is spoken in one area, with words or grammar that is slightly different. Usually, the name of the dialect is the same as the area where people speak it. For example, Wikipedia says that the Buginese language has many dialects including: Bone, Pangkep, Camba, and Luwu. If Buginese is the first language that a person learned or the language they identify their culture with, then that person can call Buginese their mother tongue. It is possible for a person to have two mother tongues. The person may have one parent that speaks Buginese and another parent who speaks Indonesian. They learned both languages at the same time.