Learn Hardcore Croatian: Učiteljica često naglasi važnu riječ u rečenici kako bismo čuli pravi naglasak. - The teacher female often emphasizes the important word in the sentence so that we hear the correct accent.

The base noun is učitelj = teacher (male, or generic in some contexts).
The suffix -ica usually makes a specifically feminine form:
- učitelj → učiteljica (male / generic → female)
- prijatelj (friend m.) → prijateljica (friend f.)

So učiteljica is grammatically and semantically feminine. If you want a male or gender‑neutral form, you use učitelj instead.

Why is the verb naglasiti used here (naglasI), and not naglašavati?

Both verbs exist, but they differ in aspect:

naglasiti = to emphasise (perfective, a single finished act)
naglašavati = to be emphasising, to emphasise repeatedly/continuously (imperfective)

In the sentence:

Učiteljica često naglasi važnu riječ...

we have the adverb često (often), which usually goes with the imperfective, but in Croatian it is also very common to use često + perfective when you mean “she repeatedly does this complete action” (each time she fully emphasises a word).

So:

Učiteljica često naglašava važnu riječ... – focuses on the ongoing/repeated process.
Učiteljica često naglasi važnu riječ... – each time, she gives it a clear, complete emphasis; this sounds very natural.

Both are possible; the given sentence is perfectly idiomatic.

What is the difference between naglasiti and naglasak?

They are related but different parts of speech:

naglasiti – verb, to emphasise, to stress (a word).
naglasak – noun, stress/accent (the actual pattern of pronunciation).

In the sentence:

naglasi važnu riječ → she emphasises an important word.
pravi naglasak → the correct stress (correct accent) of that word.

So naglasiti is what the teacher does; naglasak is what you hear.

Why is it važnu riječ and not važna riječ?

Because važnu riječ is in the accusative case, used for the direct object of the verb.

Nominative (dictionary form): važna riječ = an important word (subject)
Accusative (direct object): važnu riječ = an important word (object)

Details:

riječ is a feminine noun.
The adjective važan/važna/važno must agree with riječ in gender, number and case.
Feminine accusative singular of važan is važnu.

So:

Važna riječ je u rečenici. – The important word is in the sentence. (subject, nominative)
Naglasi važnu riječ. – Emphasise the important word. (object, accusative)

Why do we say u rečenici and not u rečenicu?

Because Croatian uses different cases with u depending on the meaning:

u + locative → location (where something is)
- u rečenici = in the sentence (static location)
u + accusative → direction / movement into
- u rečenicu = into the sentence (movement into it)

In the sentence:

...važnu riječ u rečenici...

we are talking about a word that is (located) in the sentence, not about moving a word into a sentence. Therefore u rečenici (locative) is correct.

Can the word order be Učiteljica naglasi često važnu riječ instead of Učiteljica često naglasi važnu riječ?

Technically you can say Učiteljica naglasi često važnu riječ, and it will be understood, but the most neutral and natural place for često here is before the verb:

Most natural: Učiteljica često naglasi važnu riječ...
Possible but less neutral: Učiteljica naglasi često važnu riječ...

General tendencies:

Short adverbs of frequency (često, rijetko, uvijek, nikad) very often come before the main verb.
Moving često after the verb can sound slightly more marked or emphasised, like you are contrasting with another adverb or making a stylistic choice.

For everyday speech and standard style, Učiteljica često naglasi... is the best choice.

What does kako bismo mean here, and how is it different from just kako or da?

In this context, kako bismo introduces a purpose clause:

kako bismo čuli pravi naglasak = so that we would hear the correct stress / in order for us to hear the correct stress.

Breakdown:

kako – here means so that / in order that (not how? as a question).
bismo – conditional auxiliary (1st person plural: we would).

So kako bismo čuli literally is: so that we would hear.

Differences:

kako alone (as a question) = how?
- Kako čujemo naglasak? – How do we hear the stress?
da can also introduce purpose or result:
- ...da bismo čuli pravi naglasak. – also so that we would hear the correct stress.

In purpose clauses with bismo, both kako bismo and da bismo are grammatically correct. Kako bismo often sounds a bit more formal or written; da bismo is very common; plain da čujemo is more colloquial and direct.

Why is čuli used with bismo, and why does it look like a past tense if the meaning is not past?

Croatian forms the conditional with:

bih / bi / bismo / biste / bi + past participle (the so‑called l‑participle)

So:

čuti – to hear
čuli – we/he/they heard (past participle)
bismo čuli – we would hear

It looks like a past tense form because the same participle is used in both:

Past: (Mi) smo čuli. – We heard.
Conditional: (Mi) bismo čuli. – We would hear.

In the sentence, bismo čuli is conditional, used after kako to express purpose:

...kako bismo čuli pravi naglasak.
= ...so that we would hear the correct stress.

Can we replace kako bismo čuli with da čujemo? Would the meaning change?

You can say:

Učiteljica često naglasi važnu riječ u rečenici da čujemo pravi naglasak.

This is very natural and common. The meaning is practically the same: so that we hear the correct stress.

Nuance:

kako bismo čuli – slightly more formal and explicit conditional (so that we would hear).
da čujemo – more colloquial/neutral everyday style (so that we hear / for us to hear).

In normal conversation, da čujemo is extremely common; in more careful written style, kako bismo čuli or da bismo čuli may be preferred.

What does pravi naglasak mean exactly, and could we also say točan naglasak or ispravan naglasak?

pravi naglasak literally means the real / proper stress. In this context it implies the correct, authentic way of stressing the word.
točan naglasak or ispravan naglasak both mean the correct stress.

All are understandable:

pravi naglasak – slightly more idiomatic, emphasising authentic / proper pronunciation.
točan naglasak – focuses on correctness.
ispravan naglasak – also correctness, often “fixed / not wrong”.

In teaching contexts, pravi naglasak is very common, but točan naglasak and ispravan naglasak are also fine.

How would the sentence change if the teacher were male instead of female?

You would mainly change the noun učiteljica to učitelj. The rest can stay the same:

Učitelj često naglasi važnu riječ u rečenici kako bismo čuli pravi naglasak.

The verb naglasi does not change, because Croatian verbs do not change form for grammatical gender in the present/finite forms; they change only with the subject’s person and number, and here it is still 3rd person singular.

Where does bismo have to go in the clause kako bismo čuli pravi naglasak? Could we say kako čuli bismo pravi naglasak?

Bismo is a clitic (an unstressed auxiliary) and must follow specific second‑position rules in Croatian. In a subordinate clause introduced by kako, the clitic normally goes right after the first stressed word in that clause:

Correct: kako bismo čuli pravi naglasak
Incorrect / ungrammatical: kako čuli bismo pravi naglasak

So the standard order here is:

kako (subordinating conjunction)
bismo (clitic auxiliary)
čuli (main verb)
rest of the clause

Moving bismo after čuli sounds wrong to native speakers.