Okay, imagine you have a bunch of friends who used to live in your neighborhood but now they live in many other places around the world. They still have a special connection to your neighborhood though and they all share the same culture and language. That's kind of like what the Tamil Nadu diaspora is.
Tamil Nadu is a state in India where many people speak a language called Tamil. Some of those people have moved away from Tamil Nadu to live in other parts of India or in other countries. But even though they live far away, they still have a special connection to Tamil Nadu and the Tamil language and culture.
This connection is important to them because it reminds them of their roots and where they came from. They might celebrate Tamil holidays or festivals, eat Tamil food, listen to Tamil music, and watch Tamil movies. They might also try to keep the Tamil language alive by teaching it to their children or speaking it with other Tamil people they meet.
In some parts of the world where there are a lot of Tamil people, they might even have special Tamil schools or cultural organizations where they can come together and celebrate their culture and language. So even though they live far away from Tamil Nadu, the Tamil Nadu diaspora helps keep the Tamil language and culture alive.