what

1. Origins, structure, and basic meaning

• Structure: 何 asks what something is and has the readings なに and なん.
• Basic usage: 何を持って行く asks what to bring, while 何人(なんにん) asks how many people.

2. Common pitfalls and similar expressions

• Reading with the following expression
  • Read 何を as なにを and 何ですか as なんですか. The two readings are not freely interchangeable.
• Counting people
  • For a head count, 何人 is なんにん. It asks a different question from 誰(だれ), which asks who someone is.