Some of the Dravidian languages, such as Telugu, Tamil, Malayalam, and Kannada, have a distinction between voiced and voiceless, aspirated and unaspirated only in loanwords from Indo-Aryan languages. In native Dravidian words, there is no distinction between these categories and stops are underspecified for voicing and aspiration.
What has no distinction between the categories  of voiced, voiceless, aspirated and unaspirated?
native Dravidian words