La prima strofa comincia con un accordo.

Because strofa is a feminine singular noun, so both the article and the adjective must agree with it.

• la = feminine singular the
• prima = feminine singular first
• strofa = stanza / verse

So:

• il primo verso = the first line / verse masculine
• la prima strofa = the first stanza feminine

Italian adjectives usually change form to match the noun’s gender and number.

For the same reason: strofa is feminine.
The ordinal adjective primo / prima must agree with the noun.

Agreement here is:

• prima = feminine singular
• strofa = feminine singular

Compare:

• il primo capitolo = the first chapter
• la prima pagina = the first page
• la prima strofa = the first stanza

In Italian, ordinal numbers like primo, secondo, terzo usually come before the noun.

So it is natural to say:

• la prima strofa
• il secondo verso
• la terza parte

Putting prima after the noun would sound unusual here.

Strofa usually means a stanza in a poem or a verse section in a song.

So depending on context, la prima strofa could be:

• the first stanza of a poem
• the first verse of a song

It is a common music and literature word.

Because comincia is the conjugated form of the verb, while cominciare is the infinitive.

Here the subject is la prima strofa, which is third person singular, so the verb must also be third person singular:

• cominciare = to begin
• comincia = begins

So:

• La prima strofa comincia... = The first stanza begins...

If you used cominciare, it would not be a complete, correct sentence in this context.

Because Italian usually does not need a subject pronoun when the subject is already stated or clear.

Here the subject is explicitly named:

• La prima strofa comincia con un accordo.

So adding a pronoun would be unnecessary. Italian commonly works this way.

Very often, yes. In many contexts, cominciare and iniziare both mean to begin / to start.

So these are both natural:

• La prima strofa comincia con un accordo.
• La prima strofa inizia con un accordo.

In everyday use, the difference is usually very small or nonexistent.

Because cominciare con means to begin with.

So:

• cominciare con qualcosa = to begin with something

Examples:

• Il film comincia con una scena notturna. = The film begins with a nighttime scene.
• La lezione comincia con un esercizio. = The lesson begins with an exercise.

So con is the normal preposition here.

Because accordo is a masculine singular noun, and it begins with a normal vowel sound, so the correct indefinite article is un.

Italian masculine singular indefinite articles:

• un before most words
• uno before words beginning with z, s + consonant, ps, gn, etc.

So:

• un accordo
• un amico
• uno studente
• uno zaino

Also, for masculine nouns, un before a vowel does not take an apostrophe.

Here accordo means a musical chord.

That fits the musical context of strofa, which can mean a verse of a song. So the sentence suggests that the first verse begins with a chord.

Be careful: accordo can also mean agreement in other contexts.
For example:

• un accordo commerciale = a trade agreement
• un accordo musicale = a musical chord

Context tells you which meaning is intended.

In this sentence, the articles are the normal and natural choice.

• la prima strofa = a specific first stanza
• un accordo = one chord / some chord, not identified as a specific one beforehand

Leaving them out would sound unnatural here. Italian uses articles quite often, sometimes more often than English does.

It is pronounced roughly like ko-MIN-cha.

A few useful points:

• ci before a gives a ch sound, like in church
• the stress is on min: co-MIN-cia

So comincia sounds approximately like:

• koh-MEEN-chah or ko-MIN-cha, depending on how you represent it in English

It is pronounced roughly ak-KOR-do.

Helpful points:

• the double cc is pronounced more strongly than a single c
• the stress is on cor: ac-COR-do

So it sounds approximately like:

• ahk-KOR-doh

Not naturally in standard Italian for this meaning.

The normal phrase is:

• la prima strofa

Putting prima after strofa would sound odd here and would not be the standard way to say the first stanza.

So stick with:

• La prima strofa comincia con un accordo.

It depends on what comes next.

• cominciare con
  • noun = begin with something
• cominciare a
  • infinitive = begin to do something

Examples:

• La prima strofa comincia con un accordo. = The first stanza begins with a chord.
• Il cantante comincia a cantare. = The singer begins to sing.

So both are correct, but they are used in different structures.