Bivši kralj vidi kraljicu.

Because Croatian uses case endings.

• bivši kralj is in the nominative case, which usually marks the subject
• kraljicu is in the accusative case, which usually marks the direct object

So the structure is:

• bivši kralj = the former king
• vidi = sees
• kraljicu = the queen

English mostly relies on word order to show this. Croatian uses word order too, but the endings are very important.

Because kraljicu is the accusative singular form of kraljica.

The dictionary form is:

• kraljica = queen

But after a verb like vidi when it is the thing/person being seen, Croatian uses the accusative:

• kraljica → kraljicu

So:

• kraljica = subject form
• kraljicu = object form

This is one of the most basic patterns in Croatian grammar.

Because adjectives in Croatian must agree with the noun they describe in:

• gender
• number
• case

Here, bivši describes kralj.

• kralj is masculine
• singular
• nominative (because it is the subject)

So the adjective also appears in the masculine singular nominative form:

• bivši kralj = former king

If you changed the noun, the adjective would change too. For example:

• bivša kraljica = former queen
• bivšu kraljicu = former queen (as a direct object)

Vidi is the 3rd person singular present tense of the verb vidjeti.

So it means:

• he sees
• she sees
• it sees

In this sentence, the subject is bivši kralj, so vidi means the former king sees.

A few related forms are:

• vidim = I see
• vidiš = you see
• vidi = he/she/it sees
• vidimo = we see
• vidite = you see (plural/formal)
• vide = they see

Because Croatian normally has no articles.

English says:

• the king
• a king

Croatian usually just says:

• kralj

So Bivši kralj vidi kraljicu can be understood as something like:

• The former king sees the queen
• or, depending on context, A former king sees a/the queen

The exact meaning depends on context, not on articles.

No, Croatian word order is more flexible than English word order.

The sentence Bivši kralj vidi kraljicu is the most neutral order: subject–verb–object.

But because the cases show who is doing what, Croatian can move things around for emphasis, for example:

• Kraljicu vidi bivši kralj.
• Vidi kraljicu bivši kralj.

These can still mean The former king sees the queen, but the emphasis changes.

English usually cannot do this so freely.

Yes. Bivši means former or ex-.

So:

• bivši kralj = former king / ex-king

It does not automatically mean the king is dead. It just means he is no longer king.

If you wanted to say the late king, Croatian would normally use a different word, such as pokojni.

Because kralj is the subject, so it stays in the nominative:

• kralj = king

But kraljica is the direct object, so it changes to the accusative:

• kraljica → kraljicu

So the difference is not really about the words themselves first; it is about their role in the sentence.

Also, if kralj were the object, it would change too.

Then kralj would also change form.

For masculine animate nouns, the accusative singular usually changes. So:

• kralj = king
• kralja = king (as a direct object)

And the adjective would change too:

• bivši kralj = former king
• bivšeg kralja = former king (as a direct object)

For example:

• Kraljica vidi bivšeg kralja. = The queen sees the former king.

This is a very useful comparison, because it shows that both nouns and adjectives can change form.

A rough English-friendly pronunciation is:

• Bivši ≈ BEEV-shee
• kralj ≈ kraly (with lj pronounced as one soft sound)
• vidi ≈ VEE-dee
• kraljicu ≈ kral-YEE-tsoo

Two sounds that often stand out to learners are:

• š = like sh in shoe
• lj = a soft sound, somewhat like lli in million for many learners

So the whole sentence is roughly:

BEEV-shee kraly VEE-dee kral-YEE-tsoo

That is only an approximation, but it is a helpful start.