Shrill bark is a type of vocalization made by dogs and other animals. It is characterized by a high-pitched, sharp sound that is often used to express alarm or distress. The term can be broken down into three distinct sounds: YAP (3 letters), YIP (3 letters), and YELP (4 letters). YAP is a short, sharp bark that is usually used to express excitement or joy. YIP is a higher-pitched bark that is often used to express fear or anxiety. Finally, YELP is a loud, prolonged bark that is usually used to express pain or distress.