Svakako ću ponijeti pištaljku.

Croatian often leaves out subject pronouns when they are clear from the verb form.

Here, ću tells you the subject is I:

• ću = I will

So Svakako ću ponijeti pištaljku. naturally means I will definitely bring/take a whistle.

You could say Ja ću ponijeti pištaljku, but ja is usually added only for emphasis, contrast, or clarity.

Svakako is an adverb. In this sentence it means something like:

• definitely
• certainly
• for sure
• sometimes in any case

So it adds a sense of strong certainty.

Depending on context, svakako can also mean anyway or at any rate, but here the most natural reading is definitely / certainly.

Because ću is a clitic, and Croatian clitics usually go in second position in the sentence or clause.

In:

• Svakako ću ponijeti pištaljku.

the first element is Svakako, so the clitic ću comes right after it.

This is very typical in Croatian:

• Sutra ću doći. = I will come tomorrow.
• Možda ću nazvati. = Maybe I’ll call.

So the placement is grammatical, not random.

Ću is the 1st person singular future clitic of the verb htjeti (to want), but in modern Croatian it is used as part of the future tense.

So:

• ću = I will
• ćeš = you will
• će = he/she/it will
• ćemo = we will
• ćete = you will
• će = they will

In this sentence, ću + ponijeti forms the future:

• ću ponijeti = I will bring/take along

Ponijeti is the infinitive. Croatian commonly forms the future with:

• a future clitic (ću)
• plus the infinitive

So:

• ću ponijeti = I will bring / take along

About the verb itself:

• nositi = to carry / to wear / to be carrying; usually more ongoing or habitual
• ponijeti = to take along / bring with oneself; usually a single, completed action

So ponijeti fits well if the idea is that the speaker will make sure to take a whistle with them.

This is a very common learner question.

• ponijeti = to take along / bring with oneself
• donijeti = to bring (to a destination, to someone)

Very roughly:

• ponijeti focuses on taking something with you
• donijeti focuses on bringing something to a place or person

In this sentence, ponijeti suggests I’ll take a whistle with me.

Because pištaljku is the accusative singular, and the whistle is the direct object of the verb.

Base form:

• pištaljka = a whistle (nominative singular)

Object form:

• pištaljku = a whistle (accusative singular)

For many feminine nouns ending in -a, the accusative singular ends in -u:

• knjiga → knjigu
• torba → torbu
• pištaljka → pištaljku

So after ponijeti, you need the object form pištaljku.

Yes. Pištaljka is a feminine noun.

You can tell from the dictionary form ending in -a, which is very often feminine in Croatian.

That is why:

• nominative singular: pištaljka
• accusative singular: pištaljku

Yes, Croatian word order is more flexible than English word order, but not completely free.

This sentence:

• Svakako ću ponijeti pištaljku.

is natural and neutral.

Other possible versions can shift emphasis:

• Pištaljku ću svakako ponijeti.
  Emphasizes the whistle
• Ponijet ću pištaljku.
  Also natural, especially when the infinitive comes first and shortens to ponijet

But the clitic ću still has to follow the first element of the clause.

So word order can change the focus, but not all rearrangements are equally natural.

In Croatian, when the infinitive ends in -ti, that final -i is often dropped before the future clitic in writing and speech.

So both patterns are seen:

• ću ponijeti
• ponijet ću

This is why you may come across:

• Ponijet ću pištaljku.

That is normal and standard.

But in your sentence, the structure is:

• ću + infinitive
• so it stays ću ponijeti

A few sounds may stand out to an English speaker:

• š sounds like sh in shoe
• lj is a single Croatian sound, similar to the lli in some pronunciations of million, though not exactly the same
• j is pronounced like English y

So pištaljku is approximately:

• PISH-tal-yku

Very roughly broken up:

• pi
• štalj
• ku

And pištaljka is approximately:

• PISH-tal-yka

It can depend on context.

Croatian verbs like ponijeti do not always match English bring and take perfectly. In many situations, ponijeti means:

• take along
• bring with you

So a natural translation could be:

• I’ll definitely bring a whistle.
• I’ll definitely take a whistle with me.

If the speaker is talking about making sure they have it on them, take a whistle with me is often the clearest explanation of the Croatian verb choice.