Insight into the Telugu Community in Tamil Nadu

So my girlfriend and I are both Indian-Americans. My parents are Telugu immigrants from Vijayawada in Andhra Pradesh and her parents are immigrants from Madurai in Tamil Nadu. Interestingly, despite being from Tamil Nadu, my girlfriend is 100% Telugu genetically(?) according to her (even though she identifies as both Telugu and Tamil since her ancestors have been in Tamil Nadu for centuries and have adapted to the culture). Her family has some interesting quirks. They speak what they consider to be “Telugu,” but me and my parents can barely understand it and have to talk to them in English. (Though I have been teaching my girlfriend proper Telugu, which she is appreciative of.) Likewise, they celebrate both Telugu and Tamil festivals like Ugadi and Pongal and eat both Telugu and Tamil foods. On the other hand, they rarely watch Telugu movies and don’t really know any Telugu songs. In terms of identity, her parents don’t really identify with being Telugu - they only really identify as Tamil. They took their kids to Tamil events and no Telugu events growing up. Despite this, my girlfriend and her sister tend to identify more with being Telugu, which I think is because the Telugu diaspora in America is larger than the Tamil diaspora, which makes it easier to latch on to. My girlfriend has spent pretty much our entire relationship pleading for me to explain more about Telugu culture to her haha. Is anyone on here a part of this community or have any insight about this community? I would like to learn more so that I am able to connect more with my girlfriend and her family.