Learn Hardcore Croatian: Često gledam filmove sa sestrom. - I often watch movies with my sister.

Croatian is a pro‑drop language: the verb ending already shows the subject. Gledam (ending -am) clearly means “I watch.” You add ja only for emphasis or contrast:

Gledam filmove sa sestrom. = I watch…
Ja gledam filmove sa sestrom. = I (as opposed to someone else) watch…

Why is it filmove and not filmovi?

Because it’s the direct object and must be in the accusative plural. For many masculine nouns:

Nominative plural: filmovi (subject form)
Accusative plural: filmove (object form)

A handy pattern: when the nominative plural ends in -i or -ovi (filmovi), the accusative plural often swaps that -i for -e (-ove here): filmovi → filmove. Animacy affects masculine singular accusative, but in the plural you still use the -e/-ove accusative for objects like this.

What case is sestrom, and why is it used here?

Sestrom is instrumental singular of sestra. The preposition s/sa meaning “with” requires the instrumental:

Nominative: sestra (subject)
Accusative: sestru (direct object)
Genitive: sestre
Dative/Locative: sestri
Instrumental: sestrom → after s/sa = “with (my) sister”

When do I use s vs sa?

Both mean “with” (instrumental) or “from/off” (genitive), but:

Use sa to ease pronunciation before words that start with s, z, š, ž, or a consonant cluster. Hence: sa sestrom sounds better than s sestrom.
Otherwise s is fine: s bratom, s prijateljem.
You’ll also see sa mnom (with me) and sa tobom commonly, though s mnom/s tobom aren’t wrong.

Do I need to say “my” — should it be sa svojom sestrom?

Context often makes possession obvious, so sa sestrom can be understood as “with my sister.” To be explicit (and stylistically preferred when the subject owns the noun), use the reflexive possessive:

sa svojom sestrom = with my (own) sister You can also say sa mojom sestrom, but svoj is the default when referring back to the subject.

Could I say pogledam or odgledam instead of gledam?

Not here. Gledam is imperfective (focus on the ongoing/habitual activity), which fits često (often). Pogledam/odgledam are perfective (completed, one‑off events):

Habit: Često gledam filmove. (natural)
Single completed event: Sinoć sam pogledao/odgledao film. (I watched/finished a film last night)

Where can često go? Is the word order flexible?

Yes, Croatian allows flexible word order to shift emphasis:

Neutral/frequency upfront: Često gledam filmove sa sestrom.
Slight emphasis on frequency: Gledam često filmove sa sestrom.
Emphasis on company: Sa sestrom često gledam filmove.
Emphasis on the object: Filmove često gledam sa sestrom.

All are grammatical; choose the one that highlights what you want to stress.

Can I say singular film instead of plural filmove?

You can, but the meaning shifts:

Često gledam filmove = I often watch films (in general) — the usual way to express the habit.
Često gledam film can mean “I often watch a film (on an evening),” focusing on one at a time rather than films as a category. It’s less common as a general statement.

Does gledam mean “I am watching” right now, or “I watch” in general?

Croatian has one present form for both. Context/adverbs clarify:

Habitual: Često gledam filmove… (I often watch)
Right now: Sad gledam film sa sestrom. (I’m watching a film now)

Can I drop the preposition and use just instrumental to mean “with,” like in some other languages?

No. In Croatian, accompaniment requires the preposition s/sa + instrumental. Without it, it’s ungrammatical:

Correct: (Često) gledam filmove sa sestrom.
Incorrect: ✗ gledam filmove sestrom

What happens if I use sestru instead of sestrom?

Sestru is accusative (direct object). You’d be saying “I’m watching my sister”:

Gledam sestru. = I watch/look at my sister. With “with,” you must use instrumental: sa sestrom.

How do I pronounce the special letters?

č as in English “ch” (church): Često ≈ “CHEH-stoh”
š as in “sh” (shoe): sestrom has plain s, but you’ll see š often in Croatian.
Vowels are pure and short here; r is tapped/rolled: gledam ≈ “GLEH-dahm”, filmove ≈ “FEEL-moh-veh”, sestrom ≈ “SEH-strom”.