口笛

1. Origins, structure, and basic meaning

• Structure: Written 口笛 and read くちぶえ, it is a clear pitched sound made by blowing through shaped lips, or music produced that way.
• Basic usage: It appears in a boy performing a cheerful tune and a birdlike whistle heard in a forest.

2. Common pitfalls and similar expressions

• Whistling rather than singing
  • The pitch comes from airflow at the lips rather than sung words from the voice.