When should articles be used in Bahasa Indonesia?
I am learning Indonesian and have a good understanding of how to use articles, such as the definite article "itu" and the many indefinite articles (sebuah, seorang, seekor, sebutir, etc.). However, I am not too clear on when they should be used. It seems as though they are used minimally in the language, but are there times when it is necessary to use them? I get that for a sentence such as "the man is standing", it should be "pria itu sedang berdiri", but it seems if I wanted to say "the man is standing on the table", I could simply say "pria itu sedang berdiri di atas meja", without using "meja itu". Also, if I want to say "he is riding a bike", I can say "dia sedang mengendarai sepeda" without saying "sebuah sepeda". Is it a matter of formal vs. informal speech or are there more subtle rules that I'm just not understanding?