If Mercury is in 5th House, the person is good at speculation and well prosper in stock markets and gambling. you will never fall in love with a silent person. You have to talk to them and have them talk to you---a lot. The first child will tend to be a talker too. You can express yourself creatively by writing or speaking.
He will enjoy happiness from mother, will have difficulty in having children, will be highly intelligent, soft spoken and wise. If the lord of 5th is associated with malefics or is weak, there will be loss of children. Having no children he will obtain a son by adoption. He will be sinful and will have belief in mantras.
If mercury is aspected by mars, then the person will be debauchee, liar and argumentative.
Other Views
Brihat Jatak- The person concerned will be a minister.
Phaldeepika- The native will enjoy happiness and glory on account of his brilliant intellect. The native will have many children and he will be learned in mantra shastra.
Saravali- The native will be learned in mantra shastra and hypnotism. He will have a good number of children, will be well educated, will hold a position of authority and will be happy.
Chamatkar Chintamani- The native will get children late in his life. He will be selfish and a clever hypnotist.