The word “who” is one of the most commonly used words in the English language. It can be used as an interrogative pronoun, a relative pronoun, and even a determiner. In all its forms, it has one primary purpose: to ask or introduce questions about people.

When used as an interrogative pronoun, “who” is often followed by a verb such as “is” or “our” when asking who someone or something belongs to (e.g., Who are you?); what someone’s name might be (e.g., Who said that?); where they come from (e.g., Who lives here?). It can also be followed by another noun phrase when inquiring about profession/occupation (Who is your doctor?), relationship status/family members (Who are your parents?), and more specific details like age and gender (Who was born first?).

As a relative pronoun, “who” introduces clauses that provide additional information about people already mentioned in the sentence; for example, The woman who owns this store has been running it for over ten years; He’s the man who I saw at the party last night; She’s my friend who I’ve known since high school, when introducing these clauses with “who,” we use singular verbs if referring to just one person (“He was there”) but plural verbs if referring to multiple persons(“They were talking”).

Finally, “who” can also act as a determiner before nouns when identifying specific individuals out of many possibilities – e..g., “the girl WHO won the first prize”; or “the teacher WHO taught me math.” Here again, we must pay attention to whether the singular or plural verbs should follow depending on how many persons have been identified (“won,” not “wins,”; etc.)

Understanding how different parts of speech work together will help us effectively communicate our thoughts using proper grammar rules. So next time you want to inquire about people, don’t forget that mysterious word called ‘WHO.’