Special words
It refers to local dialect.
Idioms and allusions
[source] on the unification of Chinese characters written by Zhang Taiyan in Qing Dynasty: "although today's phonology is the same, but different words are still preserved."
Discrimination of words
[usage] used as subject, object and attribute; refers to dialect
Special words
must not disobey orders and cause any delay - bù dé wéi wù