There must be many people who found conventional English language classes at school difficult and who have now taken jobs where face-to-face situations with customers and clients demand a certain facility with the language. It is for such individuals that this course is intended.
The student will probably already be appreciative of the fact that we spend a very large part of our waking lives communicating in one form or another. Therefore, it goes without saying that the more effective we are as communicators, the more effective we are as human beings.
The course content should not seem entirely unfamiliar to the student. After all, you have probably been communicating by speech since you were two years old and by writing since you were about six years old.