Learn Hardcore Croatian: Djeca pričaju tiho u učionici. - The children are talking quietly in the classroom.

Djeca is the nominative plural form meaning children (irregular plural of dijete = child). Djece is the genitive plural (of children) and cannot be used as the subject. In this sentence, the subject must be nominative, so djeca is correct.

Why is the verb pričaju (3rd person plural) and not priča (3rd person singular)?

Because the subject djeca is plural. The verb agrees with the subject in person and number: djeca pričaju = the children talk/are talking.

How do you conjugate pričati in the present tense?

Pričati (to talk, to tell) is regular:

ja pričam
ti pričaš
on/ona/ono priča
mi pričamo
vi pričate
oni/one/ona pričaju

What’s the difference between pričati and govoriti here?

Pričati = to talk, to chat, to tell (more conversational, often about content: pričati priču, pričati o nečemu).
Govoriti = to speak (ability or formal speaking, languages: govoriti engleski; formal speeches). In this sentence, pričaju suggests the children are talking/chatting quietly. Djeca govore tiho is possible but sounds more like they speak quietly (in general or in a formal sense).

Is tiho an adjective or an adverb?

Tiho is an adverb meaning quietly/softly. The related adjective is tih (m.), tiha (f.), tiho (n.) meaning quiet. Compare:

Djeca su tiha. = The children are quiet. (adjective)
Djeca pričaju tiho. = The children talk quietly. (adverb)

Can I move tiho or other words around? How flexible is word order?

Croatian word order is flexible for emphasis:

Djeca pričaju tiho u učionici. (neutral)
Djeca tiho pričaju u učionici. (slight emphasis on how)
U učionici djeca pričaju tiho. (emphasis on where)
Djeca u učionici pričaju tiho. (restricts which children) All are grammatical; the change affects focus/emphasis, not core meaning.

Why is it u učionici (locative) and not u učionicu (accusative)?

U takes:

Locative for location (where?): u učionici = in the classroom.
Accusative for movement (where to?): u učionicu = into the classroom. Here the children are already in the classroom, so locative is used.

What case is učionici, and how do you decline učionica?

Učionici is locative singular. Učionica is a regular -a feminine noun. Key forms:

Nominative sg: učionica
Accusative sg: učionicu
Genitive sg: učionice
Dative/Locative sg: učionici
Instrumental sg: učionicom Plural nominative: učionice.

Is u ever replaced by na in this kind of phrase?

For classroom as a room, use u: u učionici. Na is used with certain activities/contexts: na satu (in class, during the lesson), na nastavi (in instruction). So:

Djeca pričaju tiho u učionici. (in the room)
Djeca pričaju tiho na satu. (during the class/lesson)

Do I need an article for the in Croatian (the children)?

Croatian has no articles. Djeca can mean the children or children depending on context. To be specific, you can add a determiner:

Ta djeca = those children
Ova djeca = these children

Does the Croatian present cover both simple present and present continuous?

Yes. Djeca pričaju tiho can mean The children talk quietly (habitually) or The children are talking quietly (right now). Context clarifies which is intended.

How should I pronounce djeca, pričaju, and učionici?

Djeca: the dj is palatalized, like English dy in duty; c is ts. Approx: DYE-tsa.
Pričaju: č is a hard ch (unaspirated, like in church), not soft ć. Approx: PREE-chah-yoo.
Učionici: č = ch, c = ts. Stress typically earlier: u-ČI-o-ni-ci.

How can I intensify or modify tiho?

Common intensifiers:

vrlo tiho = very quietly (neutral/formal)
jako tiho = very/quite quietly (common)
prilično tiho = fairly quietly Comparative: tiše = more quietly. Superlative: najtiše = the most quietly.

How do I say quiet children versus children talk quietly?

Quiet children (adjective agreeing with djeca’s neuter plural): tiha djeca or mala djeca (quiet/small children).
Children talk quietly (adverb modifying the verb): Djeca pričaju tiho. Note: With djeca, adjectives take neuter plural forms (tiha, mala), not masculine or feminine plural.

If I put it in the past, how does agreement work with djeca?

Use a plural auxiliary and a neuter plural participle:

Djeca su tiho pričala u učionici. = The children talked quietly in the classroom. You may hear Djeca su pričali in speech, but standard Croatian prefers the neuter plural participle pričala with djeca.

Can I add what they are talking about? Which preposition and case?

Use o + locative:

Djeca pričaju tiho o filmu u učionici. = The children are talking quietly about the movie in the classroom. Examples of locative after o: o filmu, o knjizi, o učitelju.