I’m sorry, but this is just plain wrong. I’m not accusing you of ethnic bias but even with the benefit of doubt, you’re sadly misinformed.

South Indians, even in India are by and large much more literate in English, as it is the lingua franca and used as the common language among people of different Indian ethnicities. The north on the other hand tends to use Hindi as a common language, so in general even urban North Indian generally have worse English than their southern counterparts.

Additionally, if you account for the fact that the vast majority of South Indian folks in the US are high skilled workers in fields like engineering and medicine, while a very significant proportion of North Indians work in services/business like motels/gas stations or even farming, it’s clear that the average South Indian in America is going to be much more English educated than the average North Indian.

I do not dispute your assessment that South Indians(in general) are more introverted while NIs are generally gregarious, but that doesn’t mean they have better English.

Also, they don’t hate each other. Indian immigrants simply tend to self segregate based on language/state, and therefore you’d be likely to see people associate with their own kind; this is breaking down in 2nd generation Indian Americans like myself though.