Sutra ću isključiti mobitel prije sastanka.

Croatian normally drops subject pronouns, because the verb form already shows the person:

• ću isključiti tells us it is 1st person singular (I will turn off), so ja is not needed.

You can say:

• Ja ću isključiti mobitel sutra prije sastanka.

This is grammatically correct, but ja is usually added only for emphasis or contrast, e.g.:

• Ja ću isključiti mobitel, ali ti ga ostavi upaljenim.
  I will turn off my phone, but you leave yours on.

In Croatian, short forms like ću (called clitics) usually go in second position in the clause. In this sentence:

• Sutra (1st position)
• ću (2nd position – clitic)
• isključiti mobitel prije sastanka (rest of the clause)

Other natural orders include:

• Sutra ću isključiti mobitel prije sastanka.
• Mobitel ću sutra isključiti prije sastanka.
• Sutra ću prije sastanka isključiti mobitel.

You generally cannot put ću at the very end by itself:

• ✗ Sutra isključiti mobitel prije sastanka ću. (incorrect)

Croatian Future I is often made with:

present of htjeti (ću, ćeš, će, …) + infinitive

For ja (I):

• ja ću isključiti – I will turn off

Some full conjugation examples:

• ja ću isključiti – I will turn off
• ti ćeš isključiti – you (sg.) will turn off
• on / ona / ono će isključiti – he / she / it will turn off
• mi ćemo isključiti – we will turn off
• vi ćete isključiti – you (pl.) will turn off
• oni / one / ona će isključiti – they will turn off

Colloquially, when the infinitive is right after the auxiliary, people often drop the final -i:

• Isključit ću mobitel. (more common spelling than Isključiti ću)

Croatian verbs come in aspect pairs:

• isključiti – perfective (focus on a single completed action)
• isključivati – imperfective (focus on repeated / ongoing action)

In this sentence we talk about one specific action completed in the future:

• Sutra ću isključiti mobitel prije sastanka.
  → Tomorrow I will (once, completely) turn off my phone before the meeting.

If you said:

• Sutra ću isključivati mobitel prije sastanka.

it would sound like you repeatedly turn it off before (each) meeting – a habit, not one specific occasion. That’s why isključiti (perfective) is the natural choice.

The preposition prije (before) always takes the genitive case.

• sastanak – nominative (dictionary form, “meeting”)
• sastanka – genitive singular (“of the meeting”)

So:

• prije sastanka = before the meeting (literally: before of-meeting)

Using nominative:

• ✗ prije sastanak

is ungrammatical. You must use genitive: prije sastanka.

• mobitel is a masculine noun.
• In this sentence, it is the direct object of isključiti, so it is in the accusative singular.

For masculine inanimate nouns, nominative and accusative often look the same:

• Nominative: mobitel je na stolu. – The phone is on the table.
• Accusative: Isključujem mobitel. – I’m turning off the phone.

So mobitel here is accusative, even though it looks like nominative.

Yes, these are all natural and keep the same basic meaning:

• Sutra ću isključiti mobitel prije sastanka.
• Sutra ću prije sastanka isključiti mobitel.
• Isključit ću mobitel sutra prije sastanka.

Differences:

• All versions still mean “Tomorrow I will turn off my phone before the meeting.”
• The word order mainly affects emphasis and rhythm, not basic meaning.
  
  • Placing sutra at the beginning slightly emphasizes tomorrow.
  • Moving prije sastanka earlier can highlight before the meeting a bit more.

The important rules you must keep:

1. ću stays in (roughly) second position among the main sentence elements.
2. Preposition + noun stay together: prije sastanka cannot be split.

You can use the present in Croatian to talk about a planned future action, especially if it’s scheduled or certain:

• Sutra isključujem mobitel prije sastanka.

This sounds like a firm plan or routine, similar to English “Tomorrow I’m turning off my phone before the meeting.”

However:

• Future I (ću + infinitive) – neutral, simple future: a decision or plan.
• Present for future – often a bit more planned / scheduled / definite.

Both are correct; Sutra ću isključiti… is the most straightforward “plain future” form.

There are several common options:

• isključiti mobitel – to switch off the phone (very common, neutral).
• ugasiti mobitel – literally to extinguish, to put out; also very common in everyday speech for turning off any device.
• spremiti mobitel – to put the phone away (not exactly turn off, but often used when you’re about to stop using it).

In your sentence, you could also say:

• Sutra ću ugasiti mobitel prije sastanka.

The meaning is practically the same in everyday conversation.