"Saya" and "aku"
If you start a sentence with "saya" do you have to continue to use "saya" in the same sentence or can use switch to "aku"? For example: Saya menulisnya di telapak tangan"ku". Or does it have to be Saya menulisnya di telapak tangan "saya". I've seen this a few times and am not sure of the rule. Thanks.
It's okay to use both "Saya menulis di telapak tanganku" and "Saya menulis di telapak tangan saya", although the latter is often perceived as a formal way to express it.
saya is a formal way to represent yourself instead of aku. if you use it in real life, better use saya. But in duolingo, I guess the indonesian language still in beta progress, they need to input both words in each answer.