This English translation is unnatural.
What would be a natural translation according to you ?
I don't usually hear 'return' nor 'remember' in the present tense under this context. I'm thinking about if person A goes out of the house to an event and then just remembered he was supposed to take person B. So he comes back home and says this sentence:
"I returned because I remembered (I'm supposed to take you, too)" or what's more natural for me is "I came back because ..."
This English sentence seems to be missing verb tenses. Using past tense for both verbs would be a little more natural: "I returned because I remembered you".
Also, most English speakers would prefer "came back" instead of "returned" in this context. "I came back because I remembered you" would be closer to a natural English sentence... though even still, I don't think most English speakers would use the phrase "remembered you". I'm actually a little fuzzy on the intention behind that phrase.
Here are some English sentences that have a similar meaning but would be used in everyday speech by a native English speaker:
"I came back because I was thinking of you."
"I came back because I missed you."
Is it usual to combine a more formal pronoun with a less formal one? Or are saya and kamu around equally formal?
In written Indonesian it would be strange to use "saya" and "kamu" in the one sentence. In spoken, anything goes and there aren't really any rules, but it would probably be more common to see "aku" used in place of saya. (tbh it would be better if Duolingo just focused on using standard formal Indonesian at the beginning of the course like this, as that is what every single university course and the best private language learning institutions in Indonesia do!)
Wow no wonder I was having difficulty remembering how to say return. Can anyone explain the difference between the two?
"Kembali" means to return or come back, but "pulang" specifically means to go back home.
from what I noticed pulang means to go home, kembali is more general (for example i can use it to say I went back to Indonesia)