Demonstrative adjectives are placed in front of a noun to indicate the proximity of the noun to the speaker. A demonstrative pronoun is used to replace a noun if the noun is understood. In English, it is common to say “this one” or “these ones.” Technically, the word “this” or “these” should be used alone to replace a noun, and the word “one(s)” is unnecessary and incorrect. In Spanish, the appropriate demonstrative pronoun is used alone to replace a noun.
In Table 1, demonstrative pronouns are identical to the demonstrative adjectives. However, you may see an accent on the stressed syllable to distinguish the demonstrative pronoun from the demonstrative adjective. The accents are optional for the demonstrative pronouns.
When a demonstrative pronoun refers to an idea, situation, or concept, the appropriate neutral demonstrative pronoun is used. Since neutral demonstrative pronouns do not replace a specific noun, but rather refer to general ideas or concepts, they do not need to represent any gender and there is only one form. Notice in Table 2 that the neutral pronouns never have accent marks.
Here are some examples:
Eso es lo que te dije.
That is what I told you.
Mi niñez (Aquello que me pasó me trae tantos recuerdos.)
My childhood (That which happened to me brings back so many memories.)