Mercury in 5th house according to classical book of astrology
When Mercury in 5th house, Native will gets good knowledge and education. He may gets good happiness. He may be famous. He has many children. He may be yantric ( one who has good engineering knowledge).
When Mercury in 5th house, native will be expert in mantra. He may be endowed with happiness of children, wife, money, knowledge, fame and strength.
When Mercury in 5th house, Native will be expert in using mantra. He has many kids. He may has happiness of knowledge and happiness. He may be jolly in mood.
Mercury in 5th house is indicating Native has not good happiness of children but who always gives instructions to children.
Vridh Yavan Jatak
When Mercury in 5th house, native has few children. He has lack of sexual power. He may be involved in wicked acts. He may be fond of eating due to his hunger. He may be avoided by import person of society.