It is worth noting, I think, that old Dravidian had two words for the negative 
and positive: existential (il / uḷ) and attributive (al / ā).  Kampaṉ plays on 
these in his beautiful invocatory verse (kaṭavuḷ vāḻttu) to the Yuddhakāṇṭam:

If you say it (his way of being) is (attr.) one, it is one; if you say it is 
many, it is many;
if you say it's not (attr.) (something), it's not (that thing); if you say it is 
(attr.) (something), it is (that thing);
if you say it's not (ex.; i.e. does not exist), it's not; if you say it is (does 
exist), it does.
A fine thing, our Lord's way of being.  How, possibly, can we be saved?

The word translated "way of being", kuṭivāḻkkai, can mean "domestic life, mode 
or manner of life."

Like many Dravidian syntactical features, these are reflected in the Sanskrit I 
heard, where evam is generally used to mean "yes" in an existential sense and 
tathā in an attributive one.  It would be interesting to see if this is true in 
classical texts.  This distinction has mostly disappeared in modern Tamil but is 
still found in Malayalam, in which, I was told, there are 4 different ways each 
of saying "yes" and "no."