You should note that when the kinship terms bapak (a father) and ibu (a mother) are used as second person pronouns (i.e. meaning “you”) they are written with an initial capital letter, but when they are used in their ordinary, referential sense as kinship terms they are not capitalised (except at the beginning of a sentence, of course).
By the way, in Module 3 you learned that ibu means “a mother”, but the word given for “a father” was ayah, not bapak. There are two points to remember about this. First, bapak is the Javanese word for “a father” and ayah is the more traditionally Malay word. So you are more likely to hear ayah used in Sumatra and among educated speakers or “purists” (which is why it is used in The Indonesian Way – be grateful!). On the other hand, bapak has been enthusiastically adopted into Indonesian and you will commonly hear it used to refer to “a father”, especially in Java and among less fastidious users of the language.
Second, ayah is used to mean “you” only when you are addressing your own real father. If you are not talking to your real father, but to a “pseudo-father” you should address him as Bapak.
