Benno Landsberger and other Assyriologists argued that by examining the structure of Sumerian names of occupations, as well as toponyms and hydronyms, one can suggest that there was once an earlier group of people in the region who spoke an entirely different language-often referred to as Proto-Euphratean. Terms for "farmer", "smith", "carpenter", and "date" (as in the fruit), also do not appear to have a Sumerian or Semitic origin. Rubio challenged the Substratum hypothesis, arguing that there is evidence of borrowing from more than one language. This theory is now predominant in the field (Piotr Michalowski, Gerd Steiner, etc.).
Against this Proto-Euphratean theory, in the published version of the Sumerian Lexicon, John Alan Halloran now gives an Akkadian etymology for the Sumerian word for "carpenter":
nagar: carpenter's chisel (cf., UET 3, 0752, Obv. 2, 10, nagar mu-sar zabar, 'stylus for inscribing, in bronze'); carpenter; craftsman who built furniture, doors, boats (cf., Akk. naqaaru(m), 'to demolish, scratch, hew out, carve, engrave', maqqaarum, 'chisel', cf., Orel & Stolbova #1556 *qara‘- 'cut') [NAGAR archaic frequency: 168; concatenation of 2 sign variants]. (Halloran 2006: 186)