"The word for 'salt' (*seh_a-(e)l-)... was a major issue of discussion among linguists of the nineteenth century because it was regarded as diacritical in locating the homeland [of the Proto-Indo-European speakers] near a natural source of salt such as the Black Sea or the Aegean. In reality, salt springs and later salt mines were exploited over many areas of Eurasia since the Neolithic shift in diet that required salt for both dietary reasons (increasing consumption of cereals resulted in a reduction of salt intake from a meat diet) and for the preservation of meats." ~ Mallory & Adams, The Oxford Introduction to Proto-Indo-European and the Proto-Indo-European World (2006)

"The word sal may in fact be a remnant of a Proto-Indo-European ablaut with a root-vowel *a. This is controversial at best, and not reflected in the etymologies in our dictionary, however the bare possibility demands mentioning. "Although the evidence is sparse, it appears that roots with a as fundamental vowel also ablauted. The root *sal- 'salt' had a zero-grad *sl̥-...; the root *nas- 'nose' has a lengthened-grade derivatives such as Latin nār-ēs and English nose, both from *nās-; and the root *laku- 'body of water' (Lat. lacus 'lake', Gk. lákkos 'pond') had an o-grade form *loku- that became Scottish Gaelic loch 'lake'. The view that roots in a ablauted is not universally accepted, but these forms are difficult to explain otherwise." ~ B. Fortson, Indo-European Language and Culture (2011)