Sumerian and Indo-European: a multifarious connection

In my first post on this topic, I focused on an exploration of the connections between Sumerian and Indo-European roots and words, neglecting the possible connections with other linguistic families except some citations of Akkadian or Kartvelian parallels.

But checking these other connections is important in order to ascertain if an apparent Sumerian/Indo-European parallel is not a loan or a specific relation, but only the appearance of two results of a root which is spread in a much wider area.
Sumerian, in its apparent isolation, has been compared with very different linguistic families. One is even Austric, which seems especially strong in grammatical morphology (see here).
A more lexical comparison has been made with Dravidian, by Boisson and Sathasivam (see here).
This comparison has also been widened to Afro-Asiatic (see here).
And finally to the so called 'Nostratic', involving all these families except Austric (see here).

Some Sumerian words that we have compared with Indo-European are traced also in other linguistic families, like tab 'to burn' or zalag 'to shine' in Austric, tag 'to touch' in Afro-Asiatic and Dravidian, kur 'mountain' in Austric and Afro-Asiatic, and so on.

This can suggest that both Sumerian and Indo-European belong to a broad (Southern) Asian linguistic area, and impose caution about direct connections. But if we discover that a parallel is found only between Sumerian and Indo-European, there are more probabilities that the direct connection is there.

Another point to be considered is the possibility that different Indo-European languages lent words to Sumerian, kentum and satem for instance, in different periods.