Stan je stvarno velik.

• Stan = a noun, the subject of the sentence. It is masculine singular nominative.
• je = is, the 3rd person singular present of biti meaning to be.
• stvarno = an adverb, meaning something like really or truly here. It modifies velik.
• velik = an adjective meaning big/large. Here it is used as the predicate adjective after je.

So structurally, it is very close to:

subject + is + adverb + adjective

Serbian has no articles. Unlike English, it normally does not use separate words for a/an or the.

So stan can mean:

• an apartment
• the apartment
• just apartment in a general sense

Which one is meant depends on the context, not on an article.

Je is the normal unstressed form of is in Serbian.

• je = neutral, everyday is
• jeste = full form, usually used for emphasis, contrast, or sometimes to sound more formal

So:

• Stan je stvarno velik. = normal statement
• Stan jeste stvarno velik. = The apartment really is big with extra emphasis

For beginners, je is the form you will see most often in ordinary sentences.

This is a very common question.

In Serbian, some adjectives have a short form and a long form. With velik, the short form is often used when the adjective comes after the verb, especially after biti.

So:

• velik stan or more commonly veliki stan = a big apartment / the big apartment before the noun
• Stan je velik. = The apartment is big after the verb

In other words, velik is the natural predicate form here.

For a learner, the safest rule is:

• before a noun: usually veliki
• after je/su/etc.: often velik

Because here stvarno is an adverb, not an adjective.

It modifies velik, not stan.

• stvarno velik = really big
• velik describes the apartment
• stvarno describes the degree of velik

Adverbs in Serbian usually do not change for gender, number, or case.

Compare:

• stvaran problem = a real problem → adjective
• stvarno velik = really big → adverb + adjective

Stan is in the nominative singular, because it is the subject of the sentence.

The adjective velik agrees with the noun in:

• gender: masculine
• number: singular
• and in this kind of sentence, effectively the same basic form used with the subject

So if the subject changes, the adjective changes too:

• Soba je stvarno velika. = The room is really big.
• Mesto je stvarno veliko. = The place is really big.
• Stanovi su stvarno veliki. = The apartments are really big.

Yes, but the basic sentence order here is very natural:

Stan je stvarno velik.

Serbian word order is more flexible than English, but not totally free. One important point is that je is a clitic, so it usually comes near the second position in the clause.

That means:

• Stan je stvarno velik. = neutral, normal
• Stvarno je stan velik. = possible, but more marked; it emphasizes really
• Velik je stan. = possible, often more expressive or contrastive

So yes, the order can change, but the original version is the best neutral one for a learner.

The adjective and sometimes the verb have to agree with the noun.

Examples:

• Stan je stvarno velik.
  masculine singular

• Soba je stvarno velika.
  feminine singular

• Mesto je stvarno veliko.
  neuter singular

• Stanovi su stvarno veliki.
  masculine plural

This is one of the key patterns in Serbian: adjectives agree with the nouns they describe.

A simple English-friendly approximation is:

stahn ye STVAHR-no VEH-leek

A few notes:

• a in stan is like a in father
• j in Serbian is pronounced like English y in yes
• r in stvarno is trilled or tapped
• i in velik is like ee in see, but shorter

A more letter-by-letter guide:

• Stan = stahn
• je = ye
• stvarno = stvahr-no
• velik = veh-leek

No, not in a normal present-tense sentence like this.

In Serbian, the verb to be is usually omitted only in certain special styles, such as:

• headlines
• notes
• poetry
• very informal fragments

But in a full ordinary sentence, you need it:

• Stan je stvarno velik. = correct
• Stan stvarno velik. = not standard as a normal sentence

So for learners, keep je there.