Psalm 19:2 New English Translation

²Day after day it speaks out;^[a]
night after night it reveals his greatness.^[b]

Psalm 19:2 tn Heb “it gushes forth a word.” The “sky” (see v. 1b) is the subject of the verb. Though not literally speaking (see v. 3), it clearly reveals God’s royal majesty. The sun’s splendor and its movement across the sky is in view (see vv. 4-6).
Psalm 19:2 tn Heb “it [i.e., the sky] declares knowledge,” i.e., knowledge about God’s royal majesty and power (see v. 1). This apparently refers to the splendor and movements of the stars. The imperfect verbal forms in v. 2, like the participles in the preceding verse, combine with the temporal phrases (“day after day” and “night after night”) to emphasize the ongoing testimony of the sky.

New English Translation (NET)