Ti sada piješ kafu.

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

• piješ already means you drink / you are drinking (singular, informal)

So:

• Ti sada piješ kafu. = You are drinking coffee now.
• Sada piješ kafu. = same basic meaning

Including ti usually adds emphasis, contrast, or clarity, for example:

• Ja ne pijem kafu, ti sada piješ kafu.
  I’m not drinking coffee, you are.

Sada means now.

In everyday speech, sad is very common and means the same thing:

• Ti sada piješ kafu.
• Ti sad piješ kafu.

Both are correct.
Sada can sound a little fuller or slightly more formal, while sad is very common in conversation.

Piješ is the 2nd person singular present tense form of the verb piti (to drink).

Conjugation of piti in the present:

• ja pijem = I drink / am drinking
• ti piješ = you drink / are drinking
• on/ona/ono pije = he/she/it drinks
• mi pijemo = we drink
• vi pijete = you drink (plural or formal)
• oni/one/ona piju = they drink

So piješ specifically matches ti.

It can theoretically relate to the present, but with sada it strongly means right now, so the natural English translation is:

• You are drinking coffee now.

Without sada, Ti piješ kafu could sometimes be understood more generally depending on context:

• You drink coffee
• You are drinking coffee

Serbian present tense often covers both simple present and present progressive meanings that English separates.

Because kafu is the accusative singular form of kafa.

The verb piti is transitive, so the thing being drunk is the direct object, and that direct object goes in the accusative case.

• nominative: kafa = coffee
• accusative: kafu = coffee (as the object)

So:

• Kafa je vruća. = The coffee is hot.
  Here kafa is the subject.
• Piješ kafu. = You are drinking coffee.
  Here kafu is the object.

Yes, kafa is a feminine noun. That matters because case endings depend partly on gender and noun type.

For many feminine nouns ending in -a, the accusative singular changes -a to -u:

• kafa → kafu
• voda → vodu
• knjiga → knjigu

So kafu follows a very common pattern.

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

So kafu can mean:

• coffee
• a coffee
• the coffee

The exact meaning depends on context.

In this sentence, English usually just says:

• You are drinking coffee now.

If you need to be more specific in Serbian, you usually do it through context or other words, not articles.

No. Serbian word order is fairly flexible, though some orders sound more neutral than others.

This sentence is natural, but these are also possible:

• Sada piješ kafu.
• Ti piješ kafu sada.
• Kafu sada piješ.
• Sada ti piješ kafu.

The basic meaning stays similar, but the emphasis changes.

A neutral everyday version would often be:

• Sada piješ kafu.
• Piješ kafu sada.
• Ti sada piješ kafu. if ti is being emphasized

Yes. Ti is the informal singular word for you.

For formal singular or plural, Serbian uses vi (often written Vi with a capital letter in formal writing).

So:

• Ti sada piješ kafu. = informal singular
• Vi sada pijete kafu. = formal singular or plural

Compare:

• ti piješ
• vi pijete

Yes, aspect matters a lot in Serbian.

Piti is imperfective, which is the normal choice for an action in progress, repeated action, or general action.

That fits this sentence well:

• Ti sada piješ kafu. = You are drinking coffee now.

A related perfective verb is popiti (to drink up / finish drinking). Its present-tense forms usually refer to the future, not to an action happening right now.

So:

• Piješ kafu. = you are drinking coffee
• Popićeš kafu. = you will drink the coffee / finish the coffee

Yes, absolutely.

Piješ kafu is a perfectly normal sentence. Context would tell you whether it means:

• You’re drinking coffee
• You drink coffee

Adding sada makes the right now meaning explicit.

So:

• Piješ kafu. = context-dependent present
• Sada piješ kafu. = clearly right now

In Serbian Cyrillic, it is:

• Ти сада пијеш кафу.

Serbian regularly uses both scripts:

• Latin: Ti sada piješ kafu.
• Cyrillic: Ти сада пијеш кафу.

Both are standard.

A rough pronunciation is:

• piješ ≈ pee-yesh

More precisely:

• pi sounds like pee
• je sounds like ye
• š sounds like sh

So the whole word is close to pee-yesh.

Also:

• kafu ≈ KAH-foo
• sada ≈ SAH-dah
• ti ≈ tee

Yes, it is correct and natural.

That said, in everyday conversation a Serbian speaker might very often say one of these instead:

• Sad piješ kafu.
• Piješ kafu sad.
• Sada piješ kafu.

Using ti is natural when the speaker wants to stress you specifically. Without special emphasis, Serbian often drops it.