Indonesian Pronouns in Conversation
There are five(-ish) sets of first- and second-person singular pronouns in the Indonesian spoken in Jakarta:
Informal-colloquial pronouns: lu–gue
Casual-intimate pronouns: aku–kamu
Polite-formal pronouns: saya–Anda
Name pronouns: Khoirul, Kirana, etc.
Role pronouns: Mas, Dokter, Tante, Eyang, etc.
As a general rule of thumb, the first set of pronouns should only be used with a friend. Aku–kamu is used only with people you're familiar with. If you don't care about the nuances, you may use saya anywhere, just… try not to use Anda as it is only applicable in very specific situations—you'll just end up sounding rude. Name pronouns are mostly used by children to refer to themselves, and as for role pronouns, use 'em to refer to an older person you're talking to.
Chatting with someone your age, especially if you're still young, it is absolutely okay to use lu–gue. One nuance you may need to remember is that to refer to someone you've never met who looks about your age, politeness takes priority: refer to yourself as saya, but refer to them as Kakak, or Kak for short. Mas and Mbak are still generally acceptable, but there is an emerging group of people who protest the usage of these two terms as they sometimes coincide with classism, leading young speakers to avoid using either term completely.
Another usage for lu–gue is for cussing other people out. "Fuck you!" could be translated as "Bangsat lu!", but almost never "Bangsat kamu!", and for this reason, you should NEVER use lu–gue with a significantly older person unless you two have established that it is okay to refer to each other with these pronouns.
Aku–kamu is an interesting set of pronouns as they are commonly used outside Jakarta, among children in Jakarta, and most importantly, between lovers. This third usage is probably the most jarring for foreigners and rural speakers, as it is normally used as a colloquial set of pronouns yet has vastly different usage in Jakarta. People will forgive you for using aku–kamu; they might just stare at you weirdly. Nevertheless, it is overall still of lower risk to use than lu–gue. Unless you understand when to avoid lu–gue, just use aku–kamu.
Older people speaking to younger people may use kamu, paired with a role pronoun to refer to themself. For example, a woman speaking to their grandchild may refer to themselves as Eyang or Nenek and refer to their grandchild as kamu (or by name). Such is the case with parents, teachers, doctors, etc. Additionally, in school or college, in an attempt to come off as approachable to younger students, some older students will refer to themselves with aku, as saya can create unwanted distance. This usage is completely normal and does not come off as weird. I personally also see this more often with women, and also amongst women of the same age, but I couldn't confirm because I only know two that are my age.
Younger people speaking to older people can be differentiated into three categories: professional, familiar, and colloquial. Professionally, the younger person will use saya to refer to themselves and use role pronouns to refer to the other person (e.g., Tante, Bapak, Kakak). If already familiar, the younger person may begin to shift over to aku to refer to themselves, but still use role pronouns for the other person. In the third and final stage, when close and familiar enough, despite their age, both speakers may use lu–gue to refer to each other.
Using name pronouns to refer to yourself is oftentimes seen as childish. For this reason, as an adult, it is only used in a family setting, say, when you're speaking to your mother—you can refer to yourself by name (e.g., Khoirul) and your mother as Bu, Bunda, Ibu, or Mah. Your parents or grandparents may also refer to you by your name.
There's one obscure usage for name pronouns, that is, in surveilled conversations where aku–kamu feels too intimate. I was a victim of this when my friends criticized me after I referred to one of my friends with lu in a group discussion session which was facilitated by a professor—I ended up referring to my friends by name and avoiding pronouns completely. Aku–kamu was probably fine to use, but it's a personal preference!
Finally, for the oddball pronoun I've been avoiding: Anda. This pronoun is such a misunderstood son of a bitch because people keep using it when you're NOT SUPPOSED TO!!! In my opinion, Anda is only to be used in formal situations wherein your interlocutor is of the same age, or someone unknown. These two usages only warrant Anda to be used in debate competitions, professional settings (like guidelines or presentations), and professional insults. THAT'S IT! Do not use it anywhere else because it'll just end up sounding like the third usage.
Even us Jakartans still debate these pronoun usages—the most common situation is when you can't tell how old someone is, so you don't know whether to refer to them as kamu or Mas or Om—so some of us just try to avoid it entirely and use passive voice constructions instead. It's such a rich and nuanced aspect of the language that I take for granted. Some people hate it, some people don't mind it, but either way, it exists. And it kinda works. So we'll deal with it until the younger generation innovates simpler pronoun sets we can use in Indonesian. That's all from me today. Ciao!