The question of PIE *melgh-, 'milk', seems to have died a quiet
death.
In this form, it corresponds _exactly_ in my tables of conversions to
Arabic m-l-g, which Ishinan furnished for us.
I would analyze this as 'hang from while giving a sliding bite' = 'nurse'
properly rather than 'milk (vb.) [an animal'].
There is a Sumerian malga (for *malka[?]) in malga kalam-ma, 'milk-jar[?]
of the land', a title of the king but the evidence for this is only
circumstantial; i.e. next to non-existent (the sign for malga is,
however, written with the sign for 'drinking/eating bowl' _within_ a
jar).
Another 'longshot' is Egyptian mnH, 'froth (on lips)'.
While it appears virtually certain that the PIE and Arabic words are
related, these other possible cognates would suggest a word old enough to be
considered for S-Tib.
I am VERY reluctant to suggest a triliteral root sufficiently ancient to be
possibly found in S-Tib.
I thought this might be fun to kick around for a while � the
etymology, folks, not me!