Indefinite pronouns are very useful words. What is a pronoun? A word that you use instead of a noun. For example:
Mi amiga María estudia francés. Ella estudia francés.
Indefinite means that you are not talking about something definite or specific. Here, “ella” is my friend María, but “ella” means simply “she”, it could be any girl or woman.
Alguien abrió la puerta. Somebody opened the door.
You don’t say who did it. Was it John, you or the dog?
Now that you know what are we talking about, let’s proceed.
*ALGUIEN, NADIE (somebody, nobody):
Quiero que alguien me ayude. I want someone to help me.
Nadie me ayuda. Nobody helps me.
No quiero que nadie me ayude. I don’t want anyone to help me.
Notice that in the negative statement, you need to put “no” in front of the sentence, except when “nadie” is the first word.
*ALGO, NADA (something, nothing or anything):
Quiero algo. I want something.
Nada me gusta. I don’t like anything.
No quiero nada. I don’t want anything.
Again, you need to put “no” in front of your negative sentence, except when “nada” is in front.
*ALGUNO, ALGUNA, ALGUNOS, ALGUNAS (any, some):
They could work as pronouns or as adjectives. I give examples as pronouns. First, talking about books:
¿Alguno está en francés? Is any of them in French?
¿Algunos están en francés? Are some of them in French?
Now, talking about magazines:
¿Alguna está en italiano? Is any of them in Italian?
¿Algunas están en italiano? Are some of them in Italian?
*NINGUNO, NINGUNA (none of them):
Ninguno de estos coches es el mío. None of these cars is mine.
Ninguna de estas chaquetas es la mía. None of these jackets is mine.
When the masculine forms “uno, alguno, ninguno” are adjectives, we use the abridged versions “un, algún, ningún” followed by the noun, as in “un libro, algún libro, ningún libro”. This doesn’t affect the feminine forms, which are “una carpeta, alguna carpeta, ninguna carpeta”.
*CUALQUIERA (anyone, anybody):
¿Qué película es buena? Cualquiera. Which movie is good? Anyone.
¿Quién puede hacer esto? Cualquiera. Who can do this? Anybody.
“Cualquiera” ends with “a” but it is not a feminine word, the final “a” comes from the verb “querer”. It could be translated as “whatever you want”. So we can be talking about something feminine or masculine and we do not change this final “a”. But to speak faster, we drop the final “a” in front of nouns. Compare these two sentences:
¿Qué coche te gusta? Cualquiera. Cualquier coche me gusta.
Here you have a brief video to put everything in context. You can now read the blog about “Quantifiers” to see more of these pronouns.
www.youtube.com/watch?v=8NP78bQKDEA
