Questions & Answers about Oszczędzam dziewięćdziesiąt złotych.
Because Polish usually drops subject pronouns when the verb already shows who is doing the action.
Oszczędzam already means I save / I am saving, so ja is not necessary.
You can add ja for emphasis or contrast:
- Ja oszczędzam dziewięćdziesiąt złotych. = I am saving ninety zlotys.
It is the 1st person singular present tense form of the verb oszczędzać.
So:
- oszczędzać = to save, to economize
- oszczędzam = I save / I am saving
The ending -am is what tells you it is I.
It can mean either one.
Polish present tense often covers both:
- a habitual meaning: I save ninety zlotys
- an ongoing meaning: I am saving ninety zlotys
The exact meaning depends on context.
Also, oszczędzać is an imperfective verb, so it naturally describes an ongoing, repeated, or general action.