Psalm 78/Notes/Phrasal.V. 40.280869
From Psalms: Layer by Layer
v. 40 – When יְשִׁימוֹן appears in parallel with articular מִדְבָּר it never takes the article (see also Isa 43:19, 20; Ps 106:14; 107:4). The article is present, however, in הַיְשִׁימֹן in Num 21:20; 23:28 (possibly understood as a proper name; see the discussion in the lexical notes). Whether a particular locale or description of a desolate place (as understood here), it is quite unambiguously derived from the root √ישׁם "be desolate" (cf. Gen 47:19; Ezek 6:6; 12:19; 19:7).