extol, declare, express
謳 centers on speaking out in a strong, public way: extolling, declaring, or expressing something emphatically.
謳 combines 言 (speech) with 區, which likely contributes the sound and may suggest a container or area, giving the idea of speaking out broadly.
Words (言) coming from a container (區) like a loudspeaker: extolling and declaring for all to hear.
For オウ, imagine a poet named Ou who stands on a box (區) and uses words (言) to extol the beauty of the world: Ou -> オウ.