Δεν καταλαβαίνω το ωράριο, είναι λίγο περίεργο, δηλαδή δεν ξέρω πότε τελειώνει κάθε μάθημα.

I don’t understand the schedule, it is a bit strange, that is, I don’t know when each class finishes.

Breakdown of Δεν καταλαβαίνω το ωράριο, είναι λίγο περίεργο, δηλαδή δεν ξέρω πότε τελειώνει κάθε μάθημα.

• είμαι: to be
• λίγο: a little
• δεν: not
• πότε: when

Questions & Answers about Δεν καταλαβαίνω το ωράριο, είναι λίγο περίεργο, δηλαδή δεν ξέρω πότε τελειώνει κάθε μάθημα.

What exactly does ωράριο mean here, and how is it different from words like πρόγραμμα?

Ωράριο literally means the schedule of hours – the times during which something operates. Common meanings:

• ωράριο καταστήματος = opening hours of a shop
• ωράριο εργασίας = working hours
• ωράριο μαθημάτων = timetable of lessons (which hour each lesson starts/ends)

In your sentence it means the class schedule / timetable, especially the hours each class ends.

Πρόγραμμα is more general: program, timetable, plan (TV program, daily schedule, event program). For school you might also hear:

• ωρολόγιο πρόγραμμα = timetable (literally "hourly program")
• πρόγραμμα μαθημάτων = course schedule

So ωράριο focuses on the hours, while πρόγραμμα is the whole plan or list of activities.

Why do we say το ωράριο with the article? In English I might just say “I don’t understand the schedule”, without “the”.

In Greek, nouns very often take a definite article (ο, η, το) where English might drop it.

Here, το ωράριο means the specific schedule we’re talking about (for this school, these lessons). Without the article, δεν καταλαβαίνω ωράριο would sound strange or very abstract, like “I don’t understand schedules (as a concept)”.

So:

• Δεν καταλαβαίνω το ωράριο. = I don’t understand this schedule (the one we’re dealing with now).
  Using το is the natural, normal choice.

Why is there no “I” written in Δεν καταλαβαίνω? How do we know it means “I don’t understand”?