My son is having problem in language, reading and writing

since you did not mention your son's age, i can't really give you any specific information or suggestion. however, what really helped my kids pick up reading and writing early was the fact that i used to read out loud a lot to them. so, i will suggest that you make it a habit to read out to them everyday, and also read your own books in front of them, so that they get interested in reading. depending on age, you can encourage your kid to write a page each day, so that it develops as a habit and your child gets enough practice.