Il mio amico suona benissimo il pianoforte.

In Italian, possessives like mio, tuo, suo usually go together with the definite article:

• il mio amico = my friend
• la mia casa = my house
• i miei libri = my books

So unlike English, Italian normally says the equivalent of the my friend.

A common exception is with many singular family members:

• mia madre = my mother
• mio fratello = my brother

But amico is not a family member, so il mio amico is the normal form.

Both are possible, but they are not used in exactly the same way.

• il mio amico is the normal, neutral way to say my friend
• amico mio is more expressive or emphatic, like my dear friend or friend of mine! depending on context

So in a simple statement, il mio amico is the standard choice.

Suona comes from the verb suonare, which means to play a musical instrument.

So:

• suonare il pianoforte = to play the piano
• suonare la chitarra = to play the guitar
• suonare il violino = to play the violin

English uses play for instruments, but Italian uses suonare.

Be careful: giocare means to play in the sense of games or sports, not instruments.

• giocare a calcio = to play soccer
• suonare il pianoforte = to play the piano

Italian often leaves out subject pronouns because the verb ending usually already shows who is doing the action.

Here:

• suono = I play
• suoni = you play
• suona = he/she plays
• suoniamo = we play

Since suona already tells you it is he/she, and the noun il mio amico is stated, lui is unnecessary.

Italian uses subject pronouns mainly for emphasis, contrast, or clarity.

Benissimo is an adverb meaning very well or extremely well.

It describes how your friend plays the piano:

• suona benissimo = plays very well

It comes from bene:

• bene = well
• molto bene = very well
• benissimo = extremely well / really very well

So benissimo adds strong praise.

In Italian, adverbs like bene, benissimo, male, molto bene often come right after the verb:

• suona bene il pianoforte
• parla bene l’italiano

So suona benissimo il pianoforte is completely natural.

You may also hear:

• Il mio amico suona il pianoforte benissimo.

That is also understandable and possible, but the version with benissimo right after the verb is very common and natural.

In Italian, musical instruments normally take an article when they are the direct object of suonare:

• suonare il pianoforte
• suonare la chitarra
• suonare il flauto

English says play the piano, so in this case the two languages are actually similar.

More generally, Italian often uses the definite article with nouns in places where English might or might not.

Yes. Piano is very common in everyday speech.

• suona il piano = plays the piano
• suona il pianoforte = plays the piano

Pianoforte is the full word and may sound a bit more formal or precise, but both are correct.

Usually, yes.

• amico = male friend / masculine form
• amica = female friend / feminine form

So:

• Il mio amico suona benissimo il pianoforte.
• La mia amica suona benissimo il pianoforte.

The article and possessive also change:

• il mio amico
• la mia amica

Not normally from this sentence alone.

Amico usually means friend. In some contexts Italian speakers can use relationship words in flexible ways, but if someone clearly means boyfriend, they would more commonly say:

• il mio ragazzo = my boyfriend

So the default meaning of il mio amico is simply my friend.

It is the present indicative of suonare.

Here it means:

• he plays
• she plays

Depending on context, the Italian present can also sometimes cover ideas that English expresses with the simple present:

• habitual action: He plays the piano very well
• general fact: He is a very good piano player

But grammatically, it is the present tense.

It is pronounced roughly SWO-na.

A few helpful points:

• uo in suona makes a sound like waw/wo
• stress falls on the first syllable: SUO-na
• the s is a normal s sound

So: SUO-na.

Yes, Italian word order is more flexible than English, though some orders sound more natural than others.

These are possible:

• Il mio amico suona benissimo il pianoforte.
• Il mio amico suona il pianoforte benissimo.
• Il pianoforte il mio amico lo suona benissimo. (more marked, with emphasis)

The original sentence is a natural, straightforward way to say it.

Yes, usually.

• bene = well
• molto bene = very well
• benissimo = extremely well / really very well

In everyday speech, molto bene and benissimo can sometimes feel close, but benissimo often sounds a bit stronger or more enthusiastic.

So the sentence suggests the friend plays the piano really well.