1) I've also heard this song like years ago but I don't know if my friends have ever heard the song too, since no one was actually singing it (well at least around me haha). But looking the fact that the actual music video [ https://www.youtube.com/watch?v=A9LRYN6ta8E ] has 18 Mio views, then the song was probably quite popular (My mother also know this song hahaha) 2.1) Yes. I think because she sings so quickly, karena = kerna. The colloquial word for karena is actually "soalnya". ex. Kemarin aku tidak pergi sekolah soalnya aku sakit. 2.2) Yes, ku is the short form of 'aku' and also the possesive pronoun for I (my). But I only say 'ku' when I'm trying to say that something belongs to me rather than saying it everytime I want to say aku. --> Today I met my friend = Hari ini aku bertemu temanku. 3) Cinta has a deeper meaning than sayang, altough both means to love. CMIIW! :)

as same as Nisa said. I think she's not really popular here. and for "kerna", it's the colloquial word for karena. but I think the text on the lyric was written in Malaysian language cos I also saw the word "khabar". Although the pronounciation is the same but we usually more using "karna and kabar". cinta and sayang have almost the same meaning to love

I know Shae, but she's not popular, Popular singers here are Isyana Saraswati, Raisa, Afghan, etc. Karna, it's the shorter form, it's for informal language or daily communication. Don't use this if you write on article. I have a good recommendation if you wanna learn informal bahasa Indonesia or formal on www.bahasakita.com It's written by some lecturers. So the content is correct