Otvorite usta.

Otvorite is the imperative form of the verb otvoriti, meaning to open.

In this sentence, it can mean either:

• open! when speaking to more than one person
• open! when speaking politely/formally to one person

So Otvorite usta. is the form you would often hear from a doctor, dentist, or teacher, because it sounds either plural or polite.

The infinitive is otvoriti.

A few useful related forms are:

• otvoriti = to open
• otvarati = to be opening / to open repeatedly or over time
• otvori! = open! (to one person, informal)
• otvorite! = open! (to several people, or to one person formally)

This is one of the most confusing things for English speakers.

In Serbian, usta means mouth, but grammatically it behaves like a plural-only noun in normal usage. So even when it refers to one mouth, the form is usta.

That means Serbian says:

• otvori usta = open your mouth

not a singular form like English would make you expect.

This is just something to learn as a vocabulary fact: usta is the normal word for mouth.

Here usta is in the accusative, because it is the direct object of the verb otvorite.

You are opening what?
→ usta

For this noun, the nominative and accusative forms are the same:

• usta = mouth / mouths
• otvorite usta = open the mouth / open your mouth

So even though the case is accusative here, the form still stays usta.

In Serbian, possession is often understood from context, especially with body parts.

So Otvorite usta. naturally means Open your mouth even though there is no separate word for your.

Adding a possessive pronoun is usually unnecessary unless you want emphasis or contrast. For example:

• Otvorite usta. = Open your mouth.
• Otvorite svoja usta. = Open your own mouth.
  This sounds more emphatic and is not the neutral everyday version.

So the short version is the normal one.

Serbian often leaves out subject pronouns when they are already clear from the verb ending.

The ending -te in otvorite already tells you that the command is directed to:

• you all, or
• you in a polite/formal sense

So there is no need to say vi.

You could say:

• Vi otvorite usta.

but that usually adds emphasis or contrast. In ordinary speech, Otvorite usta. is more natural.

Use Otvori usta when speaking to one person informally:

• a friend
• a child
• someone you address with ti

Use Otvorite usta when speaking:

• to more than one person
• to one person formally/politely

So:

• Otvori usta. = singular informal
• Otvorite usta. = plural or formal singular

This difference is very important in Serbian.

Yes, the word order can change, but verb + object is the most natural order here for a command:

• Otvorite usta.

This is the standard and neutral way.

Other orders may be possible in special contexts, but they usually sound marked, poetic, or contrastive. For a basic instruction, especially in a medical setting, Otvorite usta. is exactly what you want.

This is about aspect, which is very important in Serbian.

• otvoriti = perfective
• otvarati = imperfective

In commands like this, Serbian usually uses the perfective verb when you want someone to perform one complete action:

• Otvorite usta. = Open your mouth.
  (Do it now; complete the action.)

If you used the imperfective imperative:

• Otvarajte usta.

it would sound more like:

• open your mouth repeatedly,
• keep opening your mouth,
• or do this as a repeated instruction in some broader process.

So for a single normal command, Otvorite usta. is the natural choice.

A rough English-friendly pronunciation is:

oh-TVOR-ee-teh OO-sta

A few notes:

• r is rolled or tapped
• v is like English v
• te is pronounced clearly, not reduced like English unstressed syllables often are
• u sounds like oo in food
• a is like a in father

Serbian spelling is quite regular, so once you know the sounds, pronunciation is very predictable.

By itself, Otvorite usta. is usually neutral and appropriate, especially in situations like:

• at the dentist
• at the doctor’s office
• during an examination
• in a classroom or instruction setting

It is a direct command, but that is normal in these contexts.

Because otvorite can be formal/polite, it often sounds more respectful than otvori.

Tone of voice still matters, of course. A sharp tone can make even a grammatically polite form sound rude.

Yes. Because otvorite can address more than one person, and usta is a plural-looking noun anyway, the sentence can mean:

• Open your mouth.
  (formal singular)
• Open your mouths.
  (plural)

Context tells you which one is meant.

For example:

• A dentist to one patient: Otvorite usta.
• A teacher to several students in a speaking exercise: Otvorite usta.

The Serbian form is the same.

Yes, a few very useful ones:

• Otvori usta. = Open your mouth.
  (informal singular)

• Otvorite usta, molim. = Open your mouth, please.
  (more polite)

• Otvorite malo usta. = Open your mouth a little.

• Šire otvorite usta. = Open your mouth wider.

These are very common practical variations built from the same pattern.