L'estintore è accanto alla scala antincendio.

Because Italian usually shortens il to l' before a word that begins with a vowel.

• il estintore → l'estintore

This is called elision. It is very common with singular articles before vowels.

Examples:

• l'amico = the friend
• l'uomo = the man
• l'estintore = the fire extinguisher

Here, estintore is a masculine singular noun, so the full article would normally be il, but before e- it becomes l'.

In Italian, noun gender often has to be learned together with the word. Here, estintore is masculine, so its article is il / l'.

A useful clue is that many singular masculine nouns end in -e or -ore, though this is not a perfect rule.

So:

• l'estintore = masculine singular

Its plural is:

• gli estintori = the fire extinguishers

The accent mark is important because è and e are different words in Italian.

• è = is
• e = and

So in this sentence:

• L'estintore è accanto... = The fire extinguisher is next to...

Without the accent, it would be a different word and would be incorrect here.

Accanto means next to or beside, but in Italian it is normally used with the preposition a:

• accanto a = next to / beside

So the structure is:

• accanto a + noun

In your sentence:

• accanto alla scala antincendio

This literally works like:

• next to the fire escape

You will often see:

• accanto a me = next to me
• accanto alla porta = next to the door
• accanto al tavolo = next to the table

Because in Italian, the preposition a often combines with the definite article.

Here:

• a + la = alla

So:

• accanto a la scala becomes accanto alla scala

This kind of combination is very common:

• a + il = al
• a + lo = allo
• a + l' = all'
• a + la = alla
• a + i = ai
• a + gli = agli
• a + le = alle

So alla scala means to the / at the / next to the staircase, depending on context.

Italian has a few related words:

• scala = staircase, stairway, stairs
• scale = stairs/staircases (plural)
• scalinata = a large staircase
• gradino = a single step

In this sentence, scala antincendio is a set expression meaning fire escape or fire-escape stairs. Even though English often says fire escape, Italian commonly uses scala antincendio.

So scala here does not just mean one isolated stair; it refers to the staircase/fire-escape structure.

In Italian, adjectives often come after the noun, especially when they classify or describe the type of thing.

So:

• scala antincendio = fire staircase / fire escape

Here antincendio means something like for fire safety / anti-fire / fire-protection. It is describing what kind of staircase it is.

This is very normal in Italian:

• porta antincendio = fire door
• impianto antincendio = fire protection system
• scala antincendio = fire escape

So the order is different from English, where the describing word often comes first.

Yes, in this context it functions like an adjective, even though it may feel a bit different from typical descriptive adjectives like rosso or grande.

Antincendio is often used after a noun to indicate that something is related to fire prevention or fire safety:

• estintore antincendio
• porta antincendio
• scala antincendio

It is also useful to know that words like this are often invariable, meaning they do not change form for masculine/feminine or singular/plural in the way many regular adjectives do.

A natural pronunciation is roughly:

• accanto = ahk-KAHN-toh
• alla = AHL-lah

Together:

• accanto alla sounds smooth, with the a sounds flowing together.

A rough pronunciation of the full sentence is:

les-tin-TO-reh eh ahk-KAHN-toh AHL-lah SKAH-lah an-tee-in-CHEN-dyoh

A few notes:

• cc in accanto is pronounced like a strong k sound here.
• sc in scala is just sk
• ci in incendio gives a ch sound: in-CHEN-
• gli does not appear here, so pronunciation is fairly straightforward

Yes. Vicino a is another very common way to say near or next to.

So these are both possible:

• L'estintore è accanto alla scala antincendio.
• L'estintore è vicino alla scala antincendio.

There can be a slight nuance:

• accanto a often feels more specifically right next to / beside
• vicino a can mean near, sometimes a little less exact

But in many everyday situations, they are quite close in meaning.

The structure is:

• L'estintore = subject
• è = verb
• accanto alla scala antincendio = prepositional phrase showing location

So it follows a very common Italian pattern:

[subject] + [to be] + [location]

Examples:

• Il tavolo è vicino alla finestra.
• La sedia è accanto alla porta.
• L'uscita è in fondo al corridoio.

This makes the sentence a very useful model for describing where something is.

Yes. The exact English translation depends on context.

Italian scala antincendio usually refers to the staircase structure used in emergencies, especially an exterior or dedicated emergency staircase. In English, depending on the situation, you might say:

• fire escape
• fire-escape stairs
• emergency staircase

So if you are picturing the metal stairs outside a building, fire escape is often the most natural English equivalent.