La bambina prova a mordere la mela, ma è troppo dura.

Because bambina and mela are singular feminine nouns, so they take the singular feminine definite article la.

• il = singular masculine
• la = singular feminine
• i / gli = plural masculine
• le = plural feminine

So:

• la bambina = the girl
• la mela = the apple

Provare a + infinitive is a very common Italian structure meaning to try to do something.

So:

• prova = tries
• a mordere = to bite

Together: prova a mordere = tries to bite

The preposition a is required after provare when it means to try doing something.

Examples:

• Provo a dormire. = I try to sleep.
• Proviamo a capire. = Let’s try to understand.

Provare is the infinitive, meaning to try.
In the sentence, the verb is conjugated to match the subject la bambina.

• provare = infinitive
• prova = she tries / he tries

Because la bambina is third-person singular, the correct form is prova.

Conjugation of provare in the present:

• io provo
• tu provi
• lui/lei prova
• noi proviamo
• voi provate
• loro provano

Because after prova a, Italian uses the infinitive.

So the pattern is:

[conjugated verb] + a + infinitive

Here:

• prova = conjugated verb
• a mordere = infinitive phrase

If you said prova a morde, that would be incorrect.

Yes, mordere means to bite. It can be used literally or figuratively, depending on context.

In this sentence it is literal: the girl is trying to bite the apple.

Related forms:

• mordo = I bite
• mordi = you bite
• morde = he/she bites

Italian often leaves out subject pronouns when they are clear from the verb form or the context.

So instead of saying:

• La bambina lei prova...

Italian normally just says:

• La bambina prova...

And in the second part:

• ma è troppo dura

the subject is understood from context, so lei or another noun does not need to be repeated.

This is very common in Italian.

Ma means but.

It connects the two parts of the sentence:

• La bambina prova a mordere la mela = the girl tries to bite the apple
• ma è troppo dura = but it is too hard

It works just like but in English.

Troppo means too.

Here it modifies the adjective dura:

• troppo dura = too hard

In Italian, troppo usually comes before the adjective or adverb it modifies.

Examples:

• troppo caldo = too hot
• troppo difficile = too difficult
• troppo lentamente = too slowly

Because dura is feminine singular, matching the noun it refers to: la mela.

• duro = masculine singular
• dura = feminine singular
• duri = masculine plural
• dure = feminine plural

Since mela is feminine singular, the adjective must agree:

• la mela è dura = the apple is hard

From meaning and context.

Grammatically, Italian does not repeat the subject here, so technically the subject is omitted. But the adjective dura is feminine singular, so it could match either bambina or mela, since both are feminine singular.

What tells us it refers to la mela is the logic of the sentence:

• The girl is trying to bite the apple.
• But it is too hard.

So dura clearly describes the apple.

The accent distinguishes è (is) from e (and).

• è = is
• e = and

So in this sentence:

• ma è troppo dura = but it is too hard

Without the accent, it would be a different word.

Yes. Here dura means physically hard or firm.

With food or objects, duro/dura often means:

• hard
• tough
• firm

Examples:

• pane duro = hard bread
• carne dura = tough meat

For abstract meanings like hard/difficult, Italian often uses difficile instead:

• un lavoro difficile = a difficult job/task

So in this sentence, dura is the natural word because the apple is physically hard.

Yes, that is possible, but it is slightly different in feel.

• provare a + infinitive = to try to do something
• cercare di + infinitive = to try to / to attempt to, often with a sense of making an effort

In many contexts they are similar:

• prova a mordere = tries to bite
• cerca di mordere = tries to bite / attempts to bite

In this sentence, prova a mordere sounds very natural.

The word order is quite straightforward:

La bambina | prova | a mordere | la mela, | ma | è | troppo dura

That is:

• subject = la bambina
• verb = prova
• infinitive phrase = a mordere
• object = la mela
• conjunction = ma
• verb = è
• adjective phrase = troppo dura

So the overall structure is close to English: The girl tries to bite the apple, but it is too hard.

You would change both the noun and the agreeing adjective.

Singular:

• La mela è troppo dura. = The apple is too hard.

Plural:

• Le mele sono troppo dure. = The apples are too hard.

Changes:

• la → le
• mela → mele
• è → sono
• dura → dure

Agreement is very important in Italian.