Psalm 78/Notes/Phrasal.V. 40.280869
From Psalms: Layer by Layer
v. 40 – When יְשִׁימוֹן appears in parallel with articular מִדְבָּר it never seems to take 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), this parallel perhaps being sufficient to indicate its function as a generic desert place and not a proper name. 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).