The main reasons that people find themselves looking for courses of English for adults are either: Academic, professional or personal.
Academically speaking, we find that most students are looking to enroll for a university course; often, but not always, in an English speaking country.
People motivated for professional reasons are usually looking to advance their careers, change careers, or expand into new markets. With the world´s becoming increasingly globalized, English is becoming essential in the marketplace.
Personal reasons are manifold. Maybe a student is looking to move countries, make international friends, travel, or just help their kids with their homework.
A student´s reason for studying English undoubtedly affects their motivation.
Academically motivated students will tend to see English as a ´means to an end´. They will quite probably need to pass an exam in order to attend any given university. They will need specific guidance with academic English as well as exam structure.
Professionally minded students tend to focus on what they really NEED. If they work as a telephonist, they will want to practice phone dialogues and perhaps learn the vocabulary connected with this. If, on the other hand, the student is a CEO of a company, they will be more inclined to focus on the kind of language used in high level board meetings. The key thing here, again, is what the student NEEDS. Professional / business courses tend to be much more focused on certain areas of vocabulary.
From a teacher´s perspective, teaching people motivated through personal reasons has both advantages and disadvantages. If the personal reasons are very strong, the students is likely to be highly motivated and ´switched on´ in class. This motivation will surely lead to fast progress. If, however, the reasons are more general and vague, the teacher will probably have to work a little harder and be a little more creative in motivating their students.