18 Heb “The valley will be destroyed and the tableland be laid waste.” However, in the context this surely refers to the towns and not to the valley and the tableland itself. Most commentaries see a reference to the towns in the Jordan valley referred to in Josh 13:27 and the towns mentioned in Josh 13:15–17 which were on the high tableland or high plateau or plain north of the Arnon. The mention of the towns in the first half of the verse is broader than that because it would include all the towns in the southern half of Moab between the Arnon and Zered as well as those mentioned in the second half in conjunction with the valley and the high plateau north of the Arnon.
19 Heb “which/for/as the Lord has spoken.” The first person form has again been adopted because the Lord is the speaker throughout (cf. v. 1).

In other versions

The destroyer shall come upon every city,

and no city shall escape;

the valley shall perish,

and the plain shall be destroyed,

as the Lord has spoken.

The destroyer will come against every town,

and not a town will escape.

The valley will be ruined

and the plateau destroyed,

because the Lord has spoken.

The destroyer will move against every town;

not one town will escape.

The valley will perish,

and the plain will be annihilated,

as the Lord has said.

“All the towns will be destroyed,

and no one will escape—

either on the plateaus or in the valleys,

for the Lord has spoken.

And the destroyer will come to every town,

and a town will not escape.

And the valley will be destroyed,

and the plain will be destroyed, as Yahweh has spoken.

And the spoiler shall come upon every city,

And no city shall escape:

The valley also shall perish,

And the plain shall be destroyed,

As the Lord hath spoken.

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