Perhaps, but the difference is pronunciation is not definitive evidence. For example, curry veppu (curry tree) is pronounced with the regular r sound in the st

Perhaps, but the difference is pronunciation is not definitive evidence. For example, curry veppu (curry tree) is pronounced with the regular r sound in the standard dialect, but in some dialects, it is instead kariyaappu with the dental flap r sound (the 't' in American English 'atom'). The kari for 'burnt', 'blackened' is also related to 'karuppu' for 'black', which is pronounced with the regular 'r' (like curry) instead of the dental one.