Hearing improper words contrary to religion and good manners signifies committing sin and refusing advice. Likewise, speaking without reflection and making a slip of the tongue, such as saying, 'By oath, it is not so; it is like this,' signifies repentance for a sinful and rebellious person and guidance for an unbeliever.
Seeing a person who speaks improper and useless words signifies empty and useless speech. At times, such a person signifies an imitator who speaks false and empty words, because an imitator often says pointless things to make people laugh.
Seeing someone speak improper words also signifies a person who does not keep promises or fulfill his word.