I do like heat in my dishes but not just heat, I want to taste other spices as well. I have a shelf of Indian cookbooks in my bookcase. My son-in-law was so surprised when he first took my daughter out to dinner as she was very familiar with Indian foods as I've been cooking Indian since the 80s.
My son-in-law does cook for us occasionally. He's an only child (unusual for India) and his late mom was ill much of the time so he learned to cook quite young. Yes, south Indian food is close to Sri Lankan cooking - lots of coconut (both milk and shredded), rice (I skip that) and curry leaves. The 5 southern states share some food in common although there are differences between them as they are 4 different ethnic groups with 4 different languages (the state he's from Andhra Pradesh has the hottest food). We have a lot of Tamil Sri Lankans in my part of Toronto and I have some Sri Lankan Tamil neighbours as well Tamils from Tamil Nadu, India (apparently the dialect is different, they don't always understand each other). My son-in-law lived and worked in Chennai (Madras) for 2 years and picked up a some oral Tamil but he's lost it because he doesn't use it much here. His speaks Telugu and Urdu (the 2 official languages of his state), as well as Hindi and English, the 2 national languages (he went to an English language school since he was 6 so his English is excellent). I've picked up a little bit of Hindi to use in Indian grocery stores when asking for ingredients (which is very close to Urdu in its oral form) but I find Telugu incredibly difficult to pronounce.