People from other places come to south India for their own whys and wherefores. Thus their native language or known language differs, isn’t it? The common language that you can notice to teach Tamil or even any other languages is English. Well some can find it uneasy because of being belonging to different situations. Only if you are sure that you are comfortable and thorough with English you can proceed to learn by that way or else it will complicate both the learner and the teacher.
In this contemporary trending world, we can see some sort of changes everywhere around us among public subdivisions. Well, everyone might have noticed this and is not so new in the past few decades. We have people shifted and migrated from place to place. If we go to the north of India, we will see many south Indians. Similarly, move to west there will be people from eastern side and north people in the southern part of the country as well. So, we may or may not know the reason but anyhow, it happened and is happening for certain reasons.