Popodne idem u kafić.

In Serbian, subject pronouns are often omitted because the verb ending already shows who is doing the action.

• idem = I go / I am going

So ja is not necessary here. You could say Ja idem u kafić, but that usually adds emphasis, like I’m the one going.

Idem is the 1st person singular present tense of ići (to go).

So:

• idem = I go / I’m going

Serbian present tense can often translate into English as either a simple present or a present progressive, depending on context.

Because Serbian uses different cases depending on whether there is movement toward a place or location in a place.

With u:

• u + accusative = movement into / to
• u + locative = being in

So:

• idem u kafić = I’m going to the café
• sedim u kafiću = I’m sitting in the café

Here there is motion, so accusative is used.

It is in the accusative singular.

However, for many masculine inanimate nouns, the accusative singular looks exactly the same as the nominative singular.

So:

• nominative: kafić
• accusative: kafić

That is why the form does not change visibly, even though the case has changed.

It can mean either, depending on the grammar of the sentence.

• with accusative: to / into
• with locative: in / inside

Examples:

• Idem u kafić. = I’m going to the café.
• Ja sam u kafiću. = I am in the café.

So the case after u helps tell you the meaning.

Here popodne means in the afternoon / this afternoon and functions as an adverbial expression of time.

It is very commonly used on its own without a preposition:

• Popodne idem u kafić. = I’m going to the café in the afternoon.

In many contexts, Serbian does not need a separate word like in before time expressions of this type.

Yes. Serbian word order is relatively flexible.

All of these are possible:

• Popodne idem u kafić.
• Idem popodne u kafić.
• Idem u kafić popodne.

The first one is very natural if you want to set the time first. Different word orders can slightly change emphasis, but the basic meaning stays the same.

Kafić usually means a café or coffee bar, often a casual place to sit and drink coffee or other drinks.

Related words:

• kafić = café / coffee bar
• kafana = tavern / traditional local restaurant-bar
• kafe is not the normal noun for café; kafa means coffee

So u kafić is the normal choice for to a café.

Roughly:

• ka-fić

The last letter ć is a soft sound, somewhat like a very soft ch. It is not exactly the same as English ch, but that is a useful approximation for beginners.

Also:

• č and ć are different sounds in Serbian
• kafić has ć, the softer one

Yes. ići is an imperfective verb.

That matters because imperfective verbs are commonly used for:

• ongoing actions
• repeated actions
• general movement
• planned movement in context

So Popodne idem u kafić can naturally mean something like:

• I’m going to the café this afternoon
• I go to the café in the afternoon, depending on context

If Serbian wants to emphasize a completed one-time arrival in some contexts, a perfective verb may be used instead, but idem is very normal here.

Yes, you could, but it sounds different.

• Popodne idem u kafić = very natural for a planned future action, especially when the time is already given
• Popodne ću ići u kafić = more explicitly future, but often less natural in simple everyday planning

In Serbian, the present tense is often used for a future event when the context already makes it clear, especially with a time expression like popodne.