Would 'quién' be used here or 'quien'?

Question

No tengo a nadie con quien practicar.

Would quién be used here or quien? Guides online that explain the difference are a little hard for me to understand. Which is grammatical?

Answer 1

You need to use quien because it is working as a relative pronoun that modifies nadie. Notice you can use other structures that modify nadie and it still makes sense:

• no tengo a nadie…
  • interesante.
  • que me hable en chino.
  • de Argelia.

If you wanted to turn it into a question, you'd get ¿Tengo a alguien con quien hablar? which is a yes/no question. Therefore, the quien is demonstratably not an interrogative pronoun — it's still modifying alguien.

You only use quién when it's being used as an interrogative. To do that in your sentence, you'd need to say something like

No tengo con quién practicar

...whose associated question would ¿Quién tengo con que _(puedo) hablar? Notice how it is clearly functioning here as an interrogative word, and not a relative pronoun. Otherwise, leaving it as No tengo a nadie con quién practicar is literally saying "I don't have anyone (along) with—who was that again?— to practice," which is a rather odd sentence.

Answer 2

You must use "quien" when you have to refer about a person. Example:

Ella es quien bailó toda la noche.

You must use "quién" when is a question (direct or indirect). Example:

No sé quién comió mi comida.

This is a indirect question (here is where it gets a little confusing, something that you can do is convert the sentence to a direct question):

¿Quién se comió mi comida?

Because no tengo nadie con quién practicar is a indirect question: ¿Quién practicará conmigo? you have to use "Quién"