L'ammaccatura è nella parte sbeccata.

Because la becomes l' before a word that starts with a vowel.

• la ammaccatura → l'ammaccatura

This is called elision. It makes pronunciation smoother.

Other examples:

• l'amica = the (female) friend
• l'idea = the idea
• l'acqua = the water

So ammaccatura is a feminine singular noun, and its article is shortened to l' before the vowel a.

Ammaccatura means a dent, ding, or depression caused by a hit.

It is often used for damage on:

• a car
• metal
• plastic
• furniture
• other hard surfaces

It comes from the verb ammaccare, meaning to dent or to squash in.

So:

• C'è un'ammaccatura sulla portiera. = There is a dent on the door.

Because è is the verb essere = is.

The accent is important because it distinguishes it from e, which means and.

So:

• è = is
• e = and

In your sentence:

• L'ammaccatura è... = The dent is...

Without the accent, it would be incorrect here.

Nella is a combination of:

• in = in
• la = the

So:

• in + la = nella

This is one of the common Italian preposition + article combinations.

Similar forms:

• nel = in + il
• nello = in + lo
• nei = in + i
• nelle = in + le

So nella parte literally means in the part.

In Italian, adjectives often come after the noun, especially when they describe a concrete quality.

So:

• parte sbeccata = chipped part

This is the most natural order here.

Putting the adjective before the noun is sometimes possible in Italian, but it often sounds:

• more literary
• more emphatic
• or simply unnatural with certain adjectives

With sbeccata, the normal choice is parte sbeccata.

Because sbeccata must agree with parte, and parte is feminine singular.

Italian adjectives agree in gender and number with the noun they describe.

• parte = feminine singular
• therefore: sbeccata = feminine singular

Compare:

• il bordo sbeccato = the chipped edge
• la parte sbeccata = the chipped part
• le parti sbeccate = the chipped parts

Sbeccata means chipped, especially when a small piece has broken off an edge or surface.

It is often used for things like:

• cups
• plates
• tiles
• furniture
• painted or hard surfaces

It comes from sbeccare / sbeccarsi, referring to something becoming chipped or nicked.

So la parte sbeccata is the part that is:

• chipped
• nicked
• broken at the edge

Depending on context, English might translate it in different ways.

Sometimes yes, but the nuance can be a little different.

• sbeccata often suggests a chip at the edge or a small bit broken off
• scheggiata can suggest splintered, chipped, or damaged by a fragment

In many everyday contexts, both could work, but sbeccata is very natural for something with a chipped edge or corner.

So:

• parte sbeccata = the chipped part
• parte scheggiata = the chipped/splintered part

The best choice depends on the material and type of damage.

Because the sentence describes the dent as being in/within that damaged area, not simply on top of it.

• nella parte sbeccata = in the chipped part / in the chipped area
• sulla parte sbeccata = on the chipped part

In many situations, English and Italian do not match prepositions exactly. Italian often uses in with areas, sections, or parts:

• nella parte superiore = in the upper part
• nella zona rossa = in the red area

So nella parte sbeccata sounds very natural.

Yes. Not all feminine nouns end in -a.

Parte is a very common feminine noun ending in -e.

That is why you get:

• la parte
• una parte
• la parte sbeccata

Its plural is:

• le parti

So you cannot rely only on the ending; you often need to learn the noun together with its article.

A simple pronunciation guide is:

L'ammaccatura è nella parte sbeccata
lahm-mak-ka-TOO-ra eh NEL-la PAR-te zbehk-KA-ta

A few useful points:

• ammaccatura has doubled mm, so the consonant is held a bit longer
• cc before a sounds like k
• è is an open eh
• sb in sbeccata is pronounced together, not as two separate words
• sbeccata has doubled cc, again giving a stronger k sound

If you want to sound natural, keep the rhythm smooth: lammaccaturaènellapartesbeccata

The pronoun can be omitted in Italian, but here the sentence already has its full subject noun:

• L'ammaccatura = the dent

Italian often drops subject pronouns like io, tu, lui, etc., because the verb ending already shows the person:

• Sono stanco = I am tired

But in your sentence, the subject is not a pronoun; it is a noun phrase:

• L'ammaccatura è...

So nothing is being omitted. The sentence is complete as it is.