You need a study permit to take a course that is more than six months. It tends to be difficult to obtain a study permit just to study English in Canada since CIC typically believes you are just using the study permit as a means of getting to Canada and aren't a genuine student. If you want to study in Canada, you would be better off taking a diploma or degree. You will need to make sure that the education you plan to take in Canada makes sense in light of your previous experience and education. And you'll need to make sure you can show sufficient funds to pay for your education and living expenses here (you'll most likely have to show a bank balance of at least $25K). Ideally you should take a course that is at least 2 years in length so that you can qualify for a post graduate work permit.
If your course is less than six months, then you don't need a study permit and can just apply for a regular visitor visa. There is no guarantee the visitor visa will be approved (again, CIC may suspect you are just using the visitor visa as a way of moving to Canada). Also, you won't qualify for a post graduate work permit after you finish your studies and you should expect it will be extremely difficult to find a job and employer.
