Questions & Answers about Vidím ho v parku.
Literally:
- Vidím = I see
- ho = him
- unstressed object pronoun, accusative of on (he).
- v = in
- parku = (the) park
- locative case of park (park).
So Vidím ho v parku is literally I-see him in park.
Czech word order is more flexible than English; subject pronouns (like já, I) are often omitted because the verb ending (-ím) already shows who is doing the action.
Czech usually omits subject pronouns when they’re obvious from the verb ending.
- Vidím already contains the information I
- see (1st person singular).
- You can say Já ho vidím v parku for emphasis (like English I see him in the park as opposed to someone else), but in neutral sentences you normally just say Vidím ho v parku.
So já is not wrong, just unnecessary in most contexts.