El repertorio incluye una canción nueva.

El repertorio means the repertoire or the set list/program, referring to a specific repertoire that the speaker and listener already know about.

• el repertorio = the repertoire
• un repertorio = a repertoire

So el is used when the noun is definite or already identified in context.

Repertorio usually means a collection of songs, pieces, performances, or material that a musician, singer, group, or company can perform.

Depending on context, it can mean things like:

• a performer’s repertoire
• a band’s set of songs
• the material in a show or concert program

In this sentence, it most naturally suggests a musical repertoire because of canción.

Incluir is the infinitive, meaning to include.
In the sentence, the verb is conjugated because it has a subject:

• incluir = to include
• incluye = it includes

The subject is el repertorio, which is third-person singular, so the verb must also be third-person singular:

• El repertorio incluye... = The repertoire includes...

It is only slightly irregular in spelling, not in meaning.

The infinitive is incluir, and in the present tense it goes:

• yo incluyo
• tú incluyes
• él/ella/usted incluye
• nosotros incluimos
• ustedes/ellos incluyen

The y appears in several forms: incluyo, incluyes, incluye, incluyen.

So yes, learners often notice that it is not formed exactly like a completely regular -ir verb.

In Spanish, descriptive adjectives usually come after the noun.

So the normal order is:

• una canción nueva = a new song

Putting nueva before the noun is possible in some contexts, but it can sound more literary, stylistic, or emphatic. For everyday neutral Spanish, canción nueva is the standard order.

It can depend on context.

Una canción nueva most often means a new song, but that can be understood in more than one way:

• a recently created song
• a song newly added to the repertoire
• a song the audience has not heard before

Without more context, Spanish leaves that open just like English often does.

Because canción is a feminine noun.

So the article and adjective must agree with it:

• una canción nueva
• not un canción nuevo

This is called gender agreement.

Even though canción ends in -ón, which may look unusual to beginners, it is still feminine:

• la canción
• una canción
• canción nueva

The accent mark shows the correct stress: can-CIÓN.

Without the accent, Spanish spelling rules would suggest a different stress pattern. The written accent tells you that the stress falls on the last syllable.

It is also important because accent marks are part of correct spelling in Spanish. So you should write:

• canción

not:

• cancion

A simple English-friendly approximation is:

• repertorio → reh-pehr-TOH-ryo
• canción → kahn-SYON

A few helpful notes:

• The r in repertorio is a tapped Spanish r, not a strong English r.
• The io in repertorio usually flows together smoothly.
• The ó in canción is stressed: can-CIÓN.

Because incluir does not require the personal a here.

The personal a is used before specific people (and sometimes pets or personified beings), not before things. Since una canción nueva is a thing, no a is needed.

Compare:

• El repertorio incluye una canción nueva.
• El director incluye a la cantante en el programa.

In the second sentence, a appears because la cantante is a person.

Yes. Depending on context, repertorio can often be translated in several natural ways:

• the repertoire
• the set list
• the program
• the selection of songs

If this is about a concert or performance, The set list includes a new song may sound very natural in English, even if the Spanish word is repertorio.

Yes, but incluye is more natural in many contexts.

Both can mean includes/contains, but they are used a little differently:

• incluye = includes, has as part of a whole
• contiene = contains, holds inside

For lists, programs, or repertoires, incluye usually sounds better:

• El repertorio incluye una canción nueva.

Contiene is possible, but it can sound a bit less idiomatic here.

The structure is:

Subject + verb + direct object

• El repertorio = subject
• incluye = verb
• una canción nueva = direct object

So it is a very standard Spanish sentence pattern, similar to English:

• The repertoire / includes / a new song