U službenom e-mailu skoro nikad ne stavljam uskličnik, ali u poruci prijateljici ponekad ga koristim.

Because after u meaning in, Croatian normally uses the locative case.

So:

• službeni e-mail = nominative, the basic dictionary form
• u službenom e-mailu = locative, meaning in an official/formal email

Both words change because the adjective has to agree with the noun:

• službeni → službenom
• e-mail → e-mailu

This is very common in Croatian:

• u gradu = in the city
• u školi = in school
• u službenom e-mailu = in an official email

Službenom comes from službeni, which means official, business, or formal depending on context.

In this sentence, u službenom e-mailu is best understood as:

• in a formal email
• in a business email
• in an official email

So it contrasts with the more personal tone of u poruci prijateljici.

Because Croatian normally uses double negation.

In English, you usually say:

• I almost never use...

But in Croatian, if you use a negative word like nikad (never), the verb is also negative:

• nikad ne stavljam
• literally: never not-I-put
• natural meaning: I never / almost never put

So:

• nikad stavljam ❌
• nikad ne stavljam ✅

And skoro nikad means almost never.

This is completely normal in Croatian:

• Nikad ne idem tamo. = I never go there.
• Ništa ne razumijem. = I understand nothing.
• Nikoga ne poznajem. = I know nobody.

They are frequency expressions, but they mean very different things:

• skoro nikad = almost never
• ponekad = sometimes

So the sentence contrasts two habits:

• in a formal email: almost never
• in a message to a female friend: sometimes

This contrast is reinforced by ali = but.

Yes, stavljam literally means I put / I place, from stavljati.

But Croatian often uses staviti / stavljati in places where English would say use, put in, or add.

Here, ne stavljam uskličnik means:

• I don’t put an exclamation mark
• more natural English: I don’t use an exclamation mark
• or I don’t add an exclamation mark

So it is a very natural Croatian way to say this.

Because uskličnik is the direct object, so it is in the accusative case. But for masculine inanimate nouns, the accusative singular is usually the same as the nominative singular.

So:

• nominative: uskličnik
• accusative: uskličnik

That is why the form does not change.

Compare:

• Vidim stol. = I see a table.
  (stol is masculine inanimate, so accusative = nominative)

But with masculine animate nouns, the accusative usually looks like the genitive:

• Vidim prijatelja. = I see a friend.

Since uskličnik is inanimate, the unchanged form is expected.

Ga is a short unstressed pronoun meaning him/it in the accusative singular.

Here it refers back to uskličnik:

• uskličnik = exclamation mark
• ga = it

So:

• ponekad ga koristim = sometimes I use it

Croatian often avoids repeating the noun if it is already clear.

Instead of saying:

• ponekad koristim uskličnik

the sentence says:

• ponekad ga koristim

which sounds natural and avoids repetition.

Because ga is a clitic: a short unstressed word that usually goes near the second position in the clause.

In Croatian, clitics often come early in the sentence or clause, after the first stressed element.

So after ponekad, you get:

• ponekad ga koristim

This is very natural.

You may also hear koristim ga in some contexts, but in a sentence like this, ponekad ga koristim is the standard, smooth word order.

Other examples:

• Često ga vidim. = I often see him/it.
• Neću ga zvati. = I won’t call him.
• Jučer sam ga srela. = I met him yesterday.

Prijateljici is the dative singular of prijateljica (female friend).

So:

• prijateljica = female friend
• prijateljici = to a female friend

The phrase means:

• u poruci prijateljici = in a message to a female friend

The word poruci is locative after u:

• u poruci = in a message

Then prijateljici tells you who the message is addressed to.

So the structure is roughly:

• u poruci = in a message
• prijateljici = to a female friend

Because it is the locative singular of poruka after u.

Forms of poruka:

• nominative: poruka = message
• locative: poruci = in/on a message

So:

• poruka = a message
• u poruci = in a message

This kind of change is common with feminine nouns ending in -a:

• škola → u školi
• soba → u sobi
• poruka → u poruci

Because prijateljici specifically means to a female friend.

Compare:

• prijatelj = male friend
• prijatelju = to a male friend
• prijateljica = female friend
• prijateljici = to a female friend

So the sentence is explicitly talking about writing to a female friend.

If the friend were male, it would be:

• u poruci prijatelju

They are close in meaning here, but not identical in nuance.

• ne stavljam uskličnik = I don’t put/add an exclamation mark
• ga koristim = I use it

So the first part focuses on adding the punctuation mark, while the second part focuses on using it in general.

In English, both might simply be translated as use, but Croatian often varies the wording naturally.

This makes the sentence sound less repetitive.

Because the sentence describes a general habit or usual behavior, not something happening only right now.

In Croatian, the present tense is used for habitual actions just like in English:

• skoro nikad ne stavljam... = I almost never put/use...
• ponekad ga koristim = I sometimes use it

So this is the normal tense for talking about personal habits and preferences.

Ali means but.

It introduces a contrast between two situations:

• U službenom e-mailu skoro nikad ne stavljam uskličnik
  = In a formal email, I almost never use an exclamation mark

• ali u poruci prijateljici ponekad ga koristim
  = but in a message to a female friend, I sometimes use it

So ali marks the difference between formal communication and personal communication.

Yes. Borrowed words are often adapted to Croatian grammar and declined like nouns.

So even though e-mail is originally from English, Croatian still gives it case endings:

• e-mail = nominative
• e-mailu = locative/dative singular

This is very common with loanwords in Croatian. Even borrowed nouns usually take Croatian case endings when used in sentences.

You may also see mail or other spellings in informal writing, but e-mailu is perfectly normal here.