vs
QUICK ANSWER
"Who" is a form of "who", a pronoun which is often translated as "quién". "When" is an adverb which is often translated as "cuándo". Learn more about the difference between "who" and "when" below.
who()
A pronoun is a word that stands in for a noun (e.g., she).
a. quién
Hello? Who is calling?¿Hola? ¿Quién llama?
I don't know who he is, but he looks a lot like my brother.No sé quién es, pero se parece mucho a mi hermano.
2. (relative)
when()
An adverb is a word that describes a verb, an adjective, or other adverbs (e.g., to run quickly, very tired).
A conjunction is a word that connects words, phrases, clauses, or sentences (e.g., The cat and the dog slept.).
2. (relative)
