Questions & Answers about Ja danas idem u školu brže nego moja sestra.
That is true: Serbian usually does not need the subject pronoun, because the verb ending already tells you who is doing the action.
- idem = I go / I am going
So a very neutral version would simply be:
- Danas idem u školu brže nego moja sestra.
Adding ja gives extra emphasis or contrast, for example:
- I am going faster, not someone else.
- I am the one going today.
So ja is grammatically optional here.
Serbian does not have a separate continuous form like English I am going. The present tense idem can cover several English meanings depending on context:
- I go
- I am going
- sometimes even I’m going today / I’m going later
Because the sentence has danas (today), English usually prefers I am going or I’m going today, while Serbian still just uses the normal present tense idem.
Idem is the 1st person singular present tense of ().