How do you say this in Indonesian? “good luck with your Bahasa Indonesia studies!”

See a translation

If it's translated directly, it'll be "Semoga beruntung dengan Studi Bahasa Indonesia kamu!".

However, it sounds very unnatural if you say this to your friends even though it's a proper grammar.

Instead, here are examples that you can use:

- Semoga sukses studi bahasa indonesianya!
- Semoga sukses yaah studinya!
- yang sukses yaah studi bahasa indonesianya!
- Semoga sukses!

sukses means success.
so, "Semoga sukses" means 'to wish you a luck/success in your effort of doing something' or simply is 'good luck'

Semoga beruntung is kind of similar and used in some cases. In this situation, it's going to sound a little bit unnatural.

beruntung means luck/lucky.
so, its usually pointing to someone's luck or luckiness.

For example:

I'm known as an honest student in examination amongst all my classmates ; ), i hate cheating tbh no kidding :), one of them says, "Semoga beruntung dapet nilai bagus..."(well, good luck getting your highscore....). they're basically saying, "well you don't cheat, and this is going to be hard, so you should get lucky for this test."

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and also, you probably meant 'Indonesian in natural way'.

"dalam bahasa indonesia yang natural", ini benar 👍🙂