However, there are a few variations in pronunciation that you might hear:
* Kaalai vannakam: This is a more informal way of saying it, with the emphasis on the "a" sound in "vannakam."
* Kaalai vannakka: This is another informal variation, with the "a" sound in "vannakka" being shortened.
Ultimately, all of these variations are acceptable and understood by Tamil speakers. The best way to learn the correct pronunciation is to listen to native speakers and practice saying it yourself.