Armenian աղ ał ‘salt’ (Old /äʟ/ > New /äʁ/) is usually derived from PIE *sal-, which is probably correct.
But, incidentally, neighboring Udi has 𐔴𐔾 ელ el (attested Old & New), which has a Lezgic-internal etymology: Lezgian кьел qʼel, Tsakhur qʼew, Aghul qʼˤäl, etc., even Khinalug qʼä.
