Hi,
In Korean, twitter is written as 트위터.
So if I were to write tweet, I feel 트윗 makes more sense than 트잍(this sounds more like 트 it).
Just like how Koreans write sweet as 스윗 or 스위트, not 스잍 or 스잍트. ( I feel weird seeing that) I guess if you are familiar with how Koreans sound, this will automatically make sense. But if you are not used to listening Korean, I think it is good to just memorize them at this stage.
Good luck!