Il prezzo è doppio.

In Italian, a singular countable noun usually takes an article in a normal sentence. So il prezzo is the natural way to say the price.

Using just prezzo would usually sound incomplete unless it is part of a heading, label, or a very compressed style.

Italian uses il before most masculine singular nouns. It uses lo only before certain sound combinations, such as:

• z: lo zaino
• s + consonant: lo studente
• gn: lo gnomo
• ps: lo psicologo

Since prezzo begins with pr-, it takes il: il prezzo.

È is the third-person singular present of essere, meaning is.

So:

• io sono = I am
• tu sei = you are
• lui/lei è = he/she is

Also, the accent matters:

• è = is
• e = and

Because it agrees with prezzo, which is a masculine singular noun.

Agreement in Italian works like this:

• il prezzo è doppio = masculine singular
• la tariffa è doppia = feminine singular
• i prezzi sono doppi = masculine plural
• le tariffe sono doppie = feminine plural

So doppio changes form to match the noun it describes.

Yes. In this sentence, doppio is an adjective used after essere.

This is called a predicate adjective: it describes the subject after a linking verb.

So the structure is:

• Il prezzo = subject
• è = verb
• doppio = adjective describing the subject

Yes, that is also possible, and it is very common.

A simple way to think about the difference is:

• Il prezzo è doppio = the price is double
• Il prezzo è il doppio = the price is double / the price is twice as much

Both are understandable. È il doppio often sounds especially natural when there is an implied comparison with another price, earlier amount, or expected amount.

Yes, depending on context.

In Italian, doppio often covers the idea that English expresses with either double or twice as much.

For example:

• Il prezzo è doppio = the price is double / the price is twice as much

Italian does not always need a separate word matching English twice in this kind of sentence.

A helpful approximate pronunciation is:

eel PRET-tso eh DOP-pyo

A few points:

• prezzo has tts sound in the middle: pret-tso
• è is a short open eh
• doppio has a doubled p, so the p is held a little longer: dop-pyo

The stress is:

• PREZ-zo
• DOP-pio

Because this sentence does not mean the double price as one noun phrase. It means the price is double.

So Italian uses:

• noun + essere
  • adjective
• Il prezzo è doppio

If you put the adjective before or after the noun inside one noun phrase, you change the structure:

• il doppio prezzo = the double price

That is a different construction and not the same as saying the price is double.

You need to change both the article, the noun, the verb, and the adjective:

• Il prezzo è doppio = singular
• I prezzi sono doppi = plural

Breakdown:

• il → i
• prezzo → prezzi
• è → sono
• doppio → doppi

Yes. Depending on context, Italians might also say:

• Il prezzo è raddoppiato = the price has doubled
• Il prezzo è il doppio di prima = the price is double what it was before
• Costa il doppio = it costs double / twice as much

These are not identical in every situation, but they are all common ways to express a similar idea.