Soba je prilično hladna.

Because adjectives in Croatian must agree with the noun they describe in gender, number, and case.

• soba is feminine
• it is singular
• here it is in the nominative case

So the adjective also has to be feminine singular nominative: hladna.

Compare:

• hladan = masculine
• hladna = feminine
• hladno = neuter

Je is the 3rd person singular present of biti, meaning to be. So it means is.

The sentence structure is literally:

• Soba = room
• je = is
• prilično hladna = quite cold

Because je is a clitic in Croatian. Clitics are short unstressed words that usually appear in second position in the sentence or clause.

So the neutral order is:

• Soba je prilično hladna.

A beginner should get used to seeing je after the first word or phrase, not usually at the very start of a normal statement.

It is in the nominative singular.

That is because soba is the subject of the sentence, and subjects are normally in the nominative.

Also, soba is the dictionary form of the noun.

Croatian does not have articles like English a and the.

So soba can mean:

• a room
• the room

The exact meaning depends on the context. In this sentence, English will often translate it as the room is quite cold, but Croatian does not need a separate word for the.

Here, prilično is an adverb. It modifies the adjective hladna.

It means something like:

• quite
• rather
• fairly

Unlike hladna, prilično does not change form to match the noun.

Not exactly. Prilično usually suggests a moderate degree, not an extreme one.

A rough comparison:

• malo hladna = a little cold
• prilično hladna = quite / fairly cold
• vrlo hladna or jako hladna = very cold

So prilično is usually weaker than vrlo or jako.

Not in this sentence.

Because soba is feminine, the adjective must be feminine too: hladna.

Hladno is the neuter form, so it would be used with a neuter noun, for example:

• Vrijeme je hladno. = The weather is cold.

Yes, Croatian word order is fairly flexible, but different orders can change the emphasis.

The most neutral version is:

• Soba je prilično hladna.

Other orders may sound more marked, contrastive, or dependent on context. As a learner, the neutral order is the safest one to use first.

You change je to nije:

• Soba nije prilično hladna.

That means The room is not quite cold or The room isn’t fairly cold, depending on context.

In everyday Croatian, another common phrasing is:

• Soba nije baš hladna.

That often sounds more natural for The room isn’t really that cold.

A common way is:

• Je li soba prilično hladna?

This means Is the room quite cold?

You should not normally make the question just by moving je to the front in the same way English does. Croatian usually uses je li for yes/no questions like this.