Moja sestra uvek pere lice sapunom u kupatilu.

Moja sestra is the subject of the sentence, so it is in the nominative case.

Also, moja means my and has to agree with sestra in gender, number, and case:

• sestra = feminine singular
• so the possessive adjective is moja

This is the normal way to say my sister.

Prati is the dictionary form of the verb, meaning to wash.

In the sentence, you need the present tense, third person singular, because the subject is moja sestra = my sister / she.

So:

• prati = to wash
• perem = I wash
• pereš = you wash
• pere = he/she/it washes

So moja sestra pere means my sister washes.

A useful thing to notice is that this verb changes stem in the present tense:

• infinitive: prati
• present stem: per-

That is normal for this verb.

In Serbian, you often do not need to say the possessive if it is already obvious whose body part it is.

So pere lice naturally means she washes her face.

If you say pere svoje lice, that is also correct, but it sounds more explicit or emphatic:

• pere lice = washes her face
• pere svoje lice = washes her own face / her face specifically

English usually requires her, but Serbian often leaves it out.

Lice is the direct object, so it is in the accusative case.

However, lice is a neuter singular noun, and for many neuter nouns, the nominative and accusative forms are the same.

So:

• nominative: lice
• accusative: lice

That is why it does not visibly change.

Because Serbian uses the instrumental case after the idea of with when something is used as a tool or means.

Here, soap is the thing used to wash the face, so:

• sapun = soap
• sapunom = with soap

So pere lice sapunom means washes the face with soap.

This is a very common use of the instrumental case.

After u, Serbian uses different cases depending on the meaning:

• u + accusative = movement into somewhere
• u + locative = location in somewhere

Here there is no movement into the bathroom. The action happens in the bathroom, so Serbian uses the locative:

• kupatilo = bathroom
• u kupatilu = in the bathroom

Compare:

• Idem u kupatilo. = I am going into the bathroom.
• Ja sam u kupatilu. = I am in the bathroom.

Uvek means always.

Its position is fairly natural here: after the subject and before the verb:

• Moja sestra uvek pere...

That is a common neutral placement for adverbs like always, often, never, and so on.

Serbian word order is more flexible than English, so you may also see uvek in other places, but this version sounds very normal and unmarked.

Because of uvek = always, this sentence is understood as a habitual action or general fact.

So it means something like:

• My sister always washes her face with soap in the bathroom.

Without uvek, the present tense could sometimes describe either:

• a general/habitual action, or
• something happening now, depending on context

But with uvek, the habitual meaning is clear.

That is a very common question.

Yes, prati se means to wash oneself in a general sense:

• Ona se pere. = She is washing herself.

But when Serbian names the body part directly, it often drops se:

• Ona pere lice. = She washes her face.
• Ona pere ruke. = She washes her hands.

So pere lice is completely natural.

Using se here would usually change the structure or meaning.

No, Serbian word order is fairly flexible because cases show the grammatical relationships.

This sentence has a neutral, natural order:

• subject: Moja sestra
• adverb: uvek
• verb: pere
• object: lice
• instrument: sapunom
• place: u kupatilu

Other orders are possible for emphasis, for example:

• U kupatilu moja sestra uvek pere lice sapunom.
• Moja sestra lice uvek pere sapunom u kupatilu.

But these sound more marked or stylistically different. The original sentence is the most straightforward version.

Serbian has no articles.

So nouns like sestra, lice, sapun, and kupatilo appear without words like a or the.

Whether something is understood as definite or indefinite usually comes from:

• context
• word order
• shared knowledge
• possessives such as moja

So English says:

• my sister
• the face / her face
• soap
• the bathroom

But Serbian simply says:

• moja sestra
• lice
• sapunom
• u kupatilu

Yes. Uvek is the usual Ekavian Serbian form.

You may also see uvijek, which is used in:

• Ijekavian Serbian
• Croatian
• Bosnian
• Montenegrin

So:

• uvek = always
• uvijek = always

They mean the same thing. In this sentence, uvek fits standard Ekavian Serbian.