It happens all the time that I get a request to translate a text into “Bahasa“. Bahasa means ‘language’, and nothing else. So what “Bahasa“, please?
The word bahasa is derived from the Sanskrit language, and is used for many Indian and Southeast Asian languages, but most commonly for Indonesian (bahasa Indonesia), Malay (bahasa Melayu), and Malaysian (bahasa Malaysia). So, referring to Indonesian as Bahasa is not only not correct, but also potentially misleading.
So why do so many people think that bahasa is part of the name of the Indonesian language? Some people even call it “Bahasa Indonesian”!
It is probably because Indonesians call their language bahasa Indonesia. Bahasa is an integral part that has to be attached when you refer to any language. French is bahasa Perancis, Spanish is bahasa Spanyol, and Japanese is bahasa Jepang.
Bahasa is used as a classifier for languages just as much as orang is a classifier for people, and burung a classifier for birds: a Spaniard is orang Spanyol, a Japanese orang Jepang, and a pigeon is burung merpati.
Indonesians always refer to their own language as bahasa Indonesia, never as Bahasa. A guru bahasa is a language teacher, not an Indonesian language teacher; ilmu bahasa is linguistics, tata bahasa is grammar etc.
In Indonesian, bahasa is written with lowercase /b/: It is bahasa Indonesia and not Bahasa Indonesia clearly indicating that bahasa is not part of the name of the language.
Here some common phrases using bahasa:
bahasa daerah regional language
bahasa asing foreign language
bahasa persatuan the language of unity (i.e. Indonesian)
bahasa Inggris English
bahasa Belanda Dutch
bahasa komputer computer language
bahasa isyarat sign language
berbahasa to speak a language
And finally we have bahasa tarzan or Tarzan language. This term is used when two people who speak different languages trying to communicate with each other only being able to use some rudiment phrases paired with a copious amount of sign language.