Ti si u gradu.

You are in the city.

Breakdown of Ti si u gradu.

• biti: to be
• ti: you
• grad: city
• u: in

Questions & Answers about Ti si u gradu.

Could you break down each word in Ti si u gradu. and explain its function?

Ti = “you” (singular, informal subject pronoun)
si = present tense of biti (“to be”), 2nd person singular (“are”)
u = preposition “in”
gradu = noun grad (“city”) in the locative case, singular (“in the city”)

Is the subject pronoun Ti mandatory? Can I say Si u gradu?

No, Ti is optional because the verb ending -i already shows 2nd person singular.
You can say Si u gradu, but it sounds clipped or poetic. In everyday speech you'd either keep Ti si u gradu or simply U gradu si with intonation.

What case is gradu, and why doesn’t it stay grad?

Gradu is the locative case (singular) of grad.
After preposition u for static location (“in”), masculine nouns like grad change ending to -u in locative.

How do I turn Ti si u gradu. into a question: “Are you in the city?”

Option 1: Simply use rising intonation—Ti si u gradu?
Option 2: Insert the question particle li—Jesi li u gradu? (uses the short form of “you are”: jesi)

How do I make the sentence negative: “You are not in the city”?

Negate si to nisi.
Ti nisi u gradu.
You can still drop Ti or reorder: Nisi u gradu., U gradu nisi.

What is the full present-tense conjugation of biti (“to be”)?

ja sam (I am)
ti si (you are)
on/ona/ono jest or je (he/she/it is)
mi smo (we are)
vi ste (you [pl./formal] are)
oni/one/ona su (they are)

Why isn’t there an article like the or a before gradu?

Croatian does not use definite or indefinite articles. Context replaces “a/the.”

Can I rearrange the word order for emphasis, e.g. U gradu si ti?

Yes. Croatian has flexible word order.
U gradu si ti puts more emphasis on ti (“it’s you who is in the city”).
Si ti u gradu can emphasize the verb or contrast with someone else.

Where do I put stress when pronouncing Ti si u gradu?

Primary stress falls on the first syllable of each stressed word.
TI si u GRAD-u.
Each content word (TI, si, GRAD-u) carries its own stress; function words (si, u) are lighter.