日本語を勉強していて、楽しい？ (From Human Japanese Intermediate Ch. 24)
This is translated as "Studying Japanese, is it fun?" in the lesson which got me a bit confused. Can someone explain more about what the て-form here does for the sentence? Up until now in my studies, if I wanted to ask this, it would probably be something like 日本語を勉強するのは楽しい？ or 日本語を勉強することは楽しい？
I do know that the て-form can be used to link phrases like in 猫を助けて、家に帰ります where I'll help the cat and then go home, and this is the closest usage I can think of for this case.