Ese cuaderno azul es tuyo.

Ese is a demonstrative adjective meaning that.

In Ese cuaderno azul es tuyo, ese points to a specific notebook that is not right next to the speaker. In standard Spanish, the basic distance contrast is:

• este = this
• ese = that
• aquel = that over there

So:

• Este cuaderno = this notebook
• Ese cuaderno = that notebook
• Aquel cuaderno = that notebook over there

Because cuaderno is masculine singular, the form is ese.

Because cuaderno is a masculine noun.

In Spanish, demonstratives must agree in gender and number with the noun they describe:

• este / ese / aquel for masculine singular
• esta / esa / aquella for feminine singular
• estos / esos / aquellos for masculine plural
• estas / esas / aquellas for feminine plural

So:

• ese cuaderno = that notebook
• esa libreta = that notebook/notepad

Even though a notebook is not biologically male, the noun cuaderno is grammatically masculine.

In Spanish, adjectives usually come after the noun, especially when they describe physical qualities like color, shape, size, or nationality.

So:

• cuaderno azul = blue notebook

This is the normal word order in Spanish. English usually puts the adjective before the noun, but Spanish usually puts it after.

You will sometimes see adjectives before the noun, but that often changes the tone or emphasis. For basic description, noun + adjective is the standard pattern.

Some Spanish adjectives change clearly for gender and number, and some do not change as much.

Azul:

• stays the same in the singular for masculine and feminine:

  • cuaderno azul
  • libreta azul

• changes in the plural:

  • cuadernos azules
  • libretas azules

So in this sentence, azul does not change because the noun is singular. If it were plural, it would become azules.

Because tu and tuyo do different jobs.

• tu = your → used before a noun
• tuyo = yours → used on its own, without repeating the noun

Compare:

• Ese cuaderno es tu cuaderno. = That notebook is your notebook.
• Ese cuaderno es tuyo. = That notebook is yours.

Spanish often uses possessive pronouns like tuyo, tuya, tuyos, tuyas to avoid repeating the noun.

Because tuyo must agree with the thing being possessed, not with the owner.

The thing being possessed here is cuaderno, which is masculine singular, so the correct form is tuyo.

Forms of tuyo:

• tuyo = masculine singular
• tuya = feminine singular
• tuyos = masculine plural
• tuyas = feminine plural

Examples:

• Ese cuaderno es tuyo. = That notebook is yours.
• Esa libreta es tuya. = That notebook/notepad is yours.
• Esos cuadernos son tuyos. = Those notebooks are yours.
• Esas libretas son tuyas. = Those notebooks/notepads are yours.

Es is the third-person singular form of ser, meaning is.

The subject is Ese cuaderno azul, which is a singular noun phrase, so the verb must also be singular:

• Ese cuaderno azul es tuyo. = That blue notebook is yours.

If the subject were plural, the verb would change:

• Esos cuadernos azules son tuyos. = Those blue notebooks are yours.

Spanish uses ser here because possession in this structure is expressed with ser + possessive pronoun:

• Es mío = It is mine
• Es tuyo = It is yours
• Es suyo = It is his/hers/yours/theirs

No, that is not the natural way to say it.

To express possession like is yours, Spanish normally uses:

• es tuyo

The structure de + pronoun works with some pronouns, but de ti is generally not used this way for basic possession.

Natural forms are:

• es mío = it is mine
• es tuyo = it is yours
• es suyo = it is his/hers/yours/theirs
• es nuestro = it is ours

So Ese cuaderno azul es tuyo is the normal and correct choice.

This is the most neutral and natural order:

• Ese cuaderno azul es tuyo.

Spanish word order is somewhat flexible, but not every change sounds equally natural.

For example:

• Ese cuaderno azul es tuyo. = neutral, standard
• Ese cuaderno es azul y es tuyo. = possible, but now the two ideas are separated
• Tuyo es ese cuaderno azul. = grammatically possible, but very marked or poetic

For everyday speech, the original sentence is the best model.

Yes. If the color is not important, you can say:

• Ese cuaderno es tuyo. = That notebook is yours.

Adding azul simply gives more information:

• Ese cuaderno azul es tuyo. = That blue notebook is yours.

So azul is optional in terms of grammar, but it helps identify which notebook you mean.

If yours means belonging to all of you, then in Spain you would normally use the vosotros possessive form:

• Ese cuaderno azul es vuestro. = That blue notebook is yours.
  (said to more than one person)

Forms of vuestro:

• vuestro = masculine singular
• vuestra = feminine singular
• vuestros = masculine plural
• vuestras = feminine plural

Examples:

• Ese cuaderno es vuestro.
• Esa libreta es vuestra.

This is especially relevant in Spanish from Spain, because vosotros is commonly used there.

Tuyo is pronounced roughly TOO-yoh.

A simple breakdown:

• tu sounds like too
• yo in most of Spain sounds roughly like yoh

So: TOO-yoh

Also:

• Ese ≈ EH-seh
• cuaderno ≈ kwah-DER-noh
• azul ≈ ah-THOOL in much of Spain
  (or *ah-SOOL in many other Spanish-speaking regions)*
• es ≈ ess
• tuyo ≈ TOO-yoh

The stress in the sentence falls naturally on:

• cuAderno
• azUl
• tUyo