Rule: Acquiring or Losing a Consonant in beginning of word.
Note: It is usual for words to acquire a consonant or lose one when they travel from one language to another and from this side of the border to the other. Example:
chinthu (Tamil/ Northern Dravidian) > hinthu (Hindu)(Iranian) > Hindu > þóÐ (¾Á¢ú)
in-thu (thamiz)
This has been explained by others in Is Tamil derived from Skrt thread. The same rule applies to the words of other languages given in the above post, which are compared to Tamil words.