surname Chang
Originally composed of 口 (mouth) and 日 (sun), representing a call in the morning to wake people up at sunrise to start working. Based on the original meaning "call loudly", now written as 唱. The current meaning is a phonetic loan.
《說文》：“昌，美言也。从日，从曰。一曰日光也。《詩》曰：‘東方昌矣。’，籀文昌。”
call loudly