"If he is drinking, I am eating."
Translation:Jeśli on pije, ja jem.
I wrote "jeśli on pije, jem" - why is "ja" important here? Is it for emphasis?
Because you're mentioning two different persons here, so we need the stronger contrast to clarify things.
Emphasis here is important, we have contrast between subjects. If we have a sentence with two subjects, those need to be said, especially second one.
Jem, on pije - Ok
Antek does something. Pije, ja jem. - ok
Ja jem ,on pije/ On pije , ja jem ok, more accent put on contrest between subjects
Thanks! (And since you are now on level 15 in Russian, I can tell you that "yezheli" also exists in Russian, but it sounds fancy, poetic, and outdated)