An Etymological Dictionary of the German Language/Annotated/Salz
Salz, neuter, ‘salt,’ from the equivalent Middle High German and Old High German salz, neuter; corresponding to the equivalent Gothic salt, Anglo-Saxon sealt, neuter, English salt, Dutch zout, Old Saxon salt (also an adjective Old Icelandic saltr, Anglo-Saxon sealt, ‘salty, saline’). The specifically Teutonic form sal-ta- (whence Lappish saltte) is of course related to Latin sal, Greek ἅλς; compare further Old Slovenian solĭ, Lettic sâls, Old Irish salann, ‘salt.’ The lengthened pre-Teutonic root sald appears also in Latin sallere, ‘to salt,’ with the assimilation of ld to ll; in Lithuanian the corresponding adjective saldùs has the remarkable signification ‘sweet’ (Lithuanian druskà, ‘salt,’ is connected with Lettic druska, ‘crumb.’ Among the Eastern Aryans a cognate term is wanting, the word salt, curiously enough, not being intentioned in the Rig-Veda. Perhaps the Western Aryans, in their migration, got their knowledge of the mineral from a civilised tribe that has also exercised an influence on European languages in other instances (compare Silber). That a graded form could be constructed from even a foreign term admits of no doubt (see Sülze). Perhaps the divergence between Teutonic salta- and Greek Latin sal- is due to differences anterior to the period in which the word was borrowed.