Controlla l'imbracatura, altrimenti la giostra non può partire.

Yes. In this sentence, controlla is the informal singular imperative of controllare: check.

So Controlla l'imbracatura means Check the harness when speaking to one person informally.

A learner may notice that controlla is also the he/she checks form in the present tense. That is true, but in this context the meaning is clearly imperative because it is followed by a consequence: otherwise the ride cannot start.

Related forms:

• Controlla! = check! (to one person, informal)
• Controllate! = check! (to more than one person)
• Controlli! = check! (formal singular)

Because la becomes l' before a feminine singular noun beginning with a vowel.

So:

• la imbracatura → l'imbracatura

This is called elision. It is very common in Italian.

Other examples:

• l'acqua = the water
• l'ora = the hour
• l'automobile = the car

Since imbracatura is feminine singular and starts with i, you use l'.

Imbracatura means harness. In this context, it refers to the safety restraint on a ride.

Depending on context, imbracatura can also mean a harness used in:

• climbing
• construction work
• safety equipment in general

Here, because of la giostra, it most naturally means the safety harness or restraint on an amusement ride.

Good question. Giostra can mean different things depending on context.

Common meanings include:

• carousel / merry-go-round
• fairground ride / amusement ride

In this sentence, because of the harness and cannot start, la giostra is best understood as the ride in an amusement-park sense, not necessarily a traditional carousel.

So giostra is broader than just one specific ride.

Italian uses definite articles more often than English does.

Here:

• l'imbracatura = the harness
• la giostra = the ride

Even when English might sometimes say Check your harness, Italian may naturally say Controlla l'imbracatura if the object is obvious from the situation.

Italian often prefers the article when referring to something specific and already understood from context.

Altrimenti means otherwise or or else.

In this sentence:

• Controlla l'imbracatura, altrimenti la giostra non può partire.
• Check the harness, otherwise the ride cannot start.

It introduces the consequence of not doing the first action.

You can use altrimenti in many everyday situations:

• Sbrigati, altrimenti arriviamo tardi. = Hurry up, otherwise we’ll arrive late.
• Studia, altrimenti non passerai l'esame. = Study, otherwise you won’t pass the exam.

This is a very common Italian structure:

• non = not
• può = can
• partire = to start / to leave / to depart

So:

• non può partire = cannot start

The verb potere works like a modal verb, similar to can in English, and it is followed by an infinitive:

• può partire = can start
• può entrare = can enter
• può uscire = can go out

The negation non goes before the conjugated verb:

• non può

Yes, partire often means to leave or to depart, but it is also commonly used for things that start moving or set off.

So for a ride, train, bus, or similar thing, partire can mean:

• to depart
• to set off
• to start

Examples:

• Il treno parte alle otto. = The train leaves at eight.
• La giostra parte tra un minuto. = The ride starts in one minute.

So la giostra non può partire is a very natural way to say the ride can't start.

Può is spelled with an accent because that is the correct standard spelling of the third-person singular form of potere in the present tense.

Forms of potere:

• posso = I can
• puoi = you can
• può = he/she/it can
• possiamo = we can
• potete = you can
• possono = they can

The accent is part of the written form: può, not puo.

By itself, yes, controlla could mean either:

• he/she checks
• check! (informal command)

But in this sentence, the context strongly points to the command:

• Controlla l'imbracatura, altrimenti...
• Check the harness, otherwise...

That is exactly the kind of structure used for instructions, warnings, and commands.

So while the form is ambiguous in isolation, the full sentence makes the meaning clear.

The comma separates the command from the result or warning that follows.

Structure:

• Controlla l'imbracatura = first part, the instruction
• altrimenti la giostra non può partire = second part, the consequence

This kind of punctuation is very common in both Italian and English:

• Check the harness, otherwise the ride can't start.

The comma helps make the sentence easier to read and understand.

The rest of the sentence stays the same, but the imperative changes.

Informal singular:

• Controlla l'imbracatura...

Formal singular:

• Controlli l'imbracatura...

Plural:

• Controllate l'imbracatura...

So you get:

• Controlli l'imbracatura, altrimenti la giostra non può partire.
• Controllate l'imbracatura, altrimenti la giostra non può partire.

Giostra is pronounced roughly like JOH-stra, with the gio- sounding like the jo in John, not like English gee.

A helpful breakdown:

• gio = soft j sound
• stra = stra

So:

• giostra ≈ JOH-stra

Also remember:

• gi before o gives a soft sound, like j
• the i is not pronounced as a full separate vowel here; it helps create the soft consonant sound

Yes. Se no is often used in everyday speech with a similar meaning to otherwise or or else.

So you might hear:

• Controlla l'imbracatura, se no la giostra non può partire.

That sounds natural and conversational.

A rough difference:

• altrimenti = a bit more neutral or slightly more formal
• se no = very common in spoken Italian

Both work here.