Learn Hardcore Croatian: Naša prijava za tečaj je već spremna. - Our application for the course is already ready.

Prijava (application) is a feminine noun in Croatian.
Adjectives and possessive pronouns must agree in gender, number, and case with the noun.

So:

masculine: naš tečaj (our course)
feminine: naša prijava (our application)
neuter: naše pismo (our letter)

Because prijava is feminine singular in the nominative case, you must use naša.

What case is prijava in here, and why?

In Naša prijava za tečaj je već spremna, the word prijava is in the nominative singular.

Reasons:

Prijava is the subject of the sentence (the thing that is ready).
Subjects in Croatian are normally in the nominative case.

The basic dictionary form of a noun is nominative singular, so what you see here (prijava) is that base form.

What does za tečaj mean exactly, and what case is tečaj in?

Za tečaj means for the course.

Za is a preposition meaning for, in favor of, intended for, etc.
Za is followed by the accusative case.
The noun tečaj (course) is masculine; its accusative singular is also tečaj (no change in form for many masculine nouns).

So grammatically, tečaj here is accusative singular, governed by za.

Why is there no word for the or an in this sentence?

Croatian does not use articles like English a / an / the.

Naša prijava za tečaj can mean both our course application and our application for the course.
Whether you would translate it with the or a/an depends on the context in English, but in Croatian you simply don’t mark that difference with an article.

So you just say naša prijava, without any extra word.

What is the role of je in this sentence?

Je is the 3rd person singular form of the verb biti (to be), present tense.

Literally: Naša prijava za tečaj je već spremna → Our application for the course is already ready.
Je links the subject (naša prijava za tečaj) with the predicate adjective (spremna).

It functions just like is in English:

Ona je spremna. → She is ready.
Prijava je spremna. → The application is ready.

Can I move već or je, for example: Naša prijava za tečaj već je spremna?

Yes, that is also correct: Naša prijava za tečaj već je spremna is perfectly natural.

A few notes:

Je is a clitic (an unstressed short form) and tends to appear near the beginning of the clause, usually in the second position.
Common patterns here:
- Naša prijava za tečaj je već spremna.
- Naša prijava za tečaj već je spremna.

Both are acceptable; the difference in emphasis is subtle. Spoken intonation usually carries the nuance more than the word order in this case.

Why is it spremna and not spreman or spremno?

Spreman / spremna / spremno are the masculine / feminine / neuter forms of ready.

They must agree with the gender and number of the noun they describe:

Prijava is feminine singular, so the adjective must be feminine singular: spremna.
Compare:
- Tečaj je spreman. (tečaj = masculine → spreman)
- Pismo je spremno. (pismo = neuter → spremno)
- Prijava je spremna. (prijava = feminine → spremna)

So spremna is required here to match prijava.

What is the difference between spremna and gotova? Could I say Naša prijava za tečaj je već gotova?

You can say Naša prijava za tečaj je već gotova, and it is natural.

Nuance:

Spremna = ready → prepared and in a state where it can be used or submitted.
Gotova = finished / done → the process of preparing it is complete.

In many everyday contexts, the two overlap.

Prijava je spremna – the application is ready to send.
Prijava je gotova – you’ve finished filling it out.

For a course application, both are very commonly used and usually mean practically the same thing in conversation.

Could I omit naša and just say Prijava za tečaj je već spremna?

Yes, Prijava za tečaj je već spremna is also correct.

Without naša, you are simply not specifying whose application it is.
In context, it might still be clear that you mean our application, but grammatically that information is gone.

Use naša when you want to explicitly say it’s our application.

How would this sentence change if there were several applications?

In the plural, everything that needs to agree will change:

Naše prijave za tečaj su već spremne.

Changes:

Naša prijava → Naše prijave
- naša (fem. sg.) → naše (fem. pl.)
- prijava (sg.) → prijave (pl.)
je (3rd person singular) → su (3rd person plural).
spremna (fem. sg.) → spremne (fem. pl.) to agree with prijave.

What exactly does prijava mean? Is it only application?

Prijava is a fairly broad noun built from the verb prijaviti (se) – to apply, report, register, sign up.

Depending on context, prijava can mean:

an application (for a course, job, competition)
a registration (e.g. for residence, an event)
a report (to the police, to an authority)
a login (in IT context: user login, login form)

Here, with za tečaj, the natural meaning is application for a course or course registration form.

Is there any difference between tečaj and kurs?

Both tečaj and kurs can mean course (as in a language course, training course).

In standard Croatian, tečaj is more common and more neutral.
Kurs is also understood, but many speakers feel it sounds a bit more colloquial or influenced by Serbian / older usage.

So in most standard Croatian contexts, tečaj is the safer choice:

Naša prijava za tečaj je već spremna. – fully standard and natural.

How do I pronounce tečaj and what is the difference between č and ć?

Tečaj is pronounced approximately like teh-chai in English (with a short e like in ten).

č is a hard “ch” sound, like ch in chair or church.
ć is a softer, more palatal “ch”, pronounced a bit further forward in the mouth.

In slow pronunciation:

č – stronger, sharper: čaj (tea)
ć – softer: ćao (hi/bye)

In tečaj, the consonant is č, so use the hard ch sound.