Prošli vikend razgovarala sam s njom u parku.

Croatian often leaves out subject pronouns when the verb already shows who the subject is.

In razgovarala sam:

• sam = I am as an auxiliary, and here it marks 1st person singular
• razgovarala agrees with the speaker in gender and number

So ja (I) is understood and does not need to be said.

That is how the Croatian past tense is formed.

It uses:

• the past participle: razgovarala
• plus the present-tense auxiliary biti: sam

So:

• razgovarala sam = I talked / I was talking

This is a normal Croatian past-tense pattern:

• radio sam = I worked/male speaker
• radila sam = I worked/female speaker

Because the speaker is female.

In Croatian, the past participle agrees with the subject in gender:

• razgovarao sam = I talked (male speaker)
• razgovarala sam = I talked (female speaker)

So this sentence was said by a woman.

Because the verb razgovarati normally goes with s/sa + instrumental when you say who you talked with.

So:

• razgovarati s nekim = to talk with someone

Here:

• ona = she
• njom = with her / her in the instrumental case

So:

• s njom = with her

You would not normally use nju here, because nju is accusative, not instrumental.

Because Croatian pronouns change form depending on their grammatical role.

For ona (she), some important forms are:

• ona = she
• nju = her
• njoj = to her
• njom = with her / by her

Since s requires the instrumental case, the correct form is njom.

Both s and sa mean with.

Usually:

• s is the normal shorter form
• sa is used when pronunciation is easier that way

For example:

• s njom = with her
• sa mnom = with me
• sa sestrom can also sound easier than s sestrom

In this sentence, s njom is the normal form.

Because this sentence describes location, not motion.

With u:

• u + accusative = motion into somewhere
• u + locative = being in somewhere

So:

• Idem u park. = I am going to the park.
• U parku sam. = I am in the park.

Here the speaker was talking in the park, so Croatian uses the locative:

• park → u parku

It is the locative singular of park.

The noun is:

• park = park

After u meaning in, Croatian uses the locative:

• u parku = in the park

This is a very common pattern:

• u gradu = in the city
• u restoranu = in the restaurant
• u školi = in school

Here it is functioning as a time expression, and it is usually explained as an accusative of time.

So:

• prošli vikend = last weekend

A useful detail: because vikend is a masculine inanimate noun, its accusative singular looks the same as its nominative singular. That is why the form looks unchanged.

You may also hear:

• prošlog vikenda

That is another common way to say last weekend.

Yes. Croatian word order is more flexible than English word order.

This sentence could also appear as:

• Prošli vikend sam razgovarala s njom u parku.
• S njom sam razgovarala prošli vikend u parku.
• U parku sam s njom razgovarala prošli vikend.

The basic meaning stays the same, but the emphasis changes.

A learner should know that the given version is natural, but Prošli vikend sam razgovarala... is also very common.

Because Croatian does not have articles like English a/an and the.

So u parku can mean:

• in the park
• in a park

Context tells you which meaning is intended.

That is normal in Croatian:

• imam knjigu = I have a book / the book
• vidim čovjeka = I see a man / the man

Because Croatian aspect does not work exactly like English tense.

razgovarati is an imperfective verb, and it is the normal verb for talking / having a conversation. Croatian often uses an imperfective verb in the past simply to report that an event happened.

So razgovarala sam s njom is a very normal way to say:

• I talked with her
• I was talking with her

A perfective verb such as porazgovarati can exist, but it adds a slightly different feeling, more like have a chat or talk something over as a bounded event.