upright - or, “They are of turned work, resembling a palm tree” [Maurer]. The point of comparison between the idol and the palm is in the pillar-like uprightness of the latter, it having no branches except at the top.
speak not - (Psa 115:5).
cannot go - that is, walk (Psa 115:7; Isa 46:1, Isa 46:7).