Learn Hardcore Croatian: Subotom često gledam seriju na televiziji. - On Saturdays I often watch a series on television.

Subotom često gledam seriju. = I often watch a series on Saturdays (as a routine).
U subotu gledam seriju. = I’m watching a series on Saturday (this coming one / that particular one).

You wouldn’t say just subota on its own in this position; it has to be put in the correct case for the adverbial time meaning, which here is instrumental: subotom.

What case is subotom, and is this a general pattern for days of the week?

Subotom is instrumental singular of subota.

For days of the week, Croatian regularly uses:

Accusative with “u” (u ponedjeljak, u utorak, u subotu) for one specific day.
Instrumental without a preposition (ponedjeljkom, utorkom, subotom) for habitual / repeated action on that day.

So:

U subotu idem na koncert. – This Saturday (one time).
Subotom idem na koncert. – On Saturdays (as a habit, in general).

Why is it gledam, not pogledam or something else?

Gledam is the present tense of the imperfective verb gledati (“to watch”).

Imperfective verbs (like gledati) are used for ongoing, repeated, or habitual actions.
Perfective verbs (like pogledati) are used for single, completed actions.

So for something you often do on Saturdays, the natural choice is the imperfective:

Subotom često gledam seriju. – I often watch a series (habit, process).

Subotom često pogledam seriju is grammatically possible but sounds more like “on Saturdays I often manage to finish watching a (whole) episode/series,” focusing on the completion, not the general habit.

Why is there no “I” (ja) in the sentence? Is it optional?

Croatian is a “pro-drop” language, meaning the subject pronoun is normally left out when the verb ending already shows the person.

Gledam clearly shows 1st person singular (“I watch”), so ja is not needed.

You can say:

Ja subotom često gledam seriju na televiziji.

This is correct but usually adds emphasis on “I” (for example, contrasting with someone else): “I (as opposed to others) often watch a series on Saturdays.” In neutral, everyday speech, you normally omit ja here.

Why is it seriju and not serija?

Seriju is the accusative singular form of serija (a feminine noun).

In Croatian, the direct object of a verb like gledati (“to watch”) is put in the accusative case:

Nominative: serija (subject) – Serija je zanimljiva.
Accusative: seriju (object) – Gledam seriju.

So because serija is the thing being watched, it has to be seriju, not serija.

What is the difference between seriju and serije in this kind of sentence?

Both are derived from serija, but they’re different forms:

Seriju – accusative singular: “a series / one series” as a direct object.
Serije – most often accusative plural: “series (plural)” as a direct object.

Examples:

Gledam seriju. – I’m watching a (one) series.
Gledam serije. – I watch series (plural), / I watch TV series (in general, more than one).

In your sentence, seriju suggests you have one particular show / series you habitually watch at that time.

Why is it na televiziji and not just televiziju or televizija?

The phrase na televiziji literally means “on television” (as a medium), and this is the natural way to say “on TV” in Croatian.

Televizija is the nominative form (“Television is…”)
Televiziju (accusative) as an object: Gledam televiziju. = “I watch TV” (in general).
Na televiziji (locative with na): Gledam seriju na televiziji. = “I’m watching a series on TV.”

So in this sentence, televizija is not the direct object; it’s a location/medium, which is why we use na + locative: na televiziji.

What case is televiziji, and why does na use that case here?

Televiziji is the locative singular of televizija.

The preposition na can take:

Locative when it means “on / in” as a location or medium (no movement).
Accusative when it means “onto” (movement toward a place).

Here, you’re not moving anywhere; you’re describing where the series is being watched: on television as a medium. So:

Gledam seriju na televiziji. – locative: static location/medium.
Stavljam knjigu na televizor. – accusative: movement “onto the TV set”.

Is there a difference between na televiziji and na televizoru?

Yes, there’s a nuance:

Na televiziji – “on TV” as a medium or channel. This is what you use for shows, news, series, films:
- Gledam seriju na televiziji. – I’m watching a series on TV.
Na televizoru – “on the TV set / on the television (device)” – more about the physical object or screen:
- Ne ostavljaj čašu na televizoru. – Don’t leave the glass on the TV.

In everyday speech, when talking about programs, people overwhelmingly say na televiziji or colloquially na TV-u.

Can the word order change? For example, can I say Često subotom gledam seriju na televiziji or Gledam seriju na televiziji često subotom?

Yes. Croatian word order is much more flexible than English, and all these are grammatical:

Subotom često gledam seriju na televiziji.
Često subotom gledam seriju na televiziji.
Često gledam seriju na televiziji subotom.
Gledam seriju na televiziji često subotom.

The basic meaning stays the same, but the emphasis changes slightly depending on what you put earlier in the sentence (often “old” / known information first, “new” / emphasized information later).

For a neutral, textbook-like version, Subotom često gledam seriju na televiziji or Često subotom gledam seriju na televiziji are the most typical.

Where can I put često in the sentence, and does its position change the meaning?

Često is an adverb (“often”), and it can appear in several positions:

Subotom često gledam seriju na televiziji. – very natural.
Često subotom gledam seriju na televiziji. – slightly more emphasis on how often this happens.
Subotom gledam često seriju na televiziji. – possible, but this position (between verb and object) is less common and can sound a bit marked.

The core meaning (frequency = often) doesn’t change, but moving često affects what feels emphasized or where the rhythm of the sentence is. Safest and most typical: Subotom često gledam… or Često subotom gledam….

Why doesn’t Croatian use articles here, like “a series” or “the series”?

Croatian simply does not have articles like English “a/an” or “the”.

Seriju by itself can mean “a series” or “the series”, depending on context.
Similarly, na televiziji can be understood as “on (the) television” without an explicit article.

So you don’t need to think about adding any word equivalent to “a” or “the” – it’s all handled by context and word order, not by a separate article word.

Could I say Subotom često gledam serije na televiziji instead of seriju?

Yes, but it changes the meaning slightly.

Gledam seriju – suggests one specific series (for example, your favorite show) that you usually watch on Saturdays.
Gledam serije – suggests multiple series or TV shows in general; maybe your Saturday habit is to watch various series.

Both forms are grammatically correct; you just choose singular (seriju) or plural (serije) depending on what you want to say.