嚷 can mean shouting loudly or complaining/fussing repeatedly. 嚷嚷 (rāngrāng) is the reduplicated form meaning 'to make a racket' and is more colloquial.
mistakes
Note the tone difference: 嚷 (rǎng, 3rd tone) when used alone, but 嚷嚷 (rāngrāng, 1st tone) when reduplicated.
口 on the left is the mouth radical, a square outline of an open mouth. It tags 嚷 as a vocal action, grouping it with 喊 (shout), 叫 (call), and 吵 (squabble) - words for things produced loudly out of the mouth.
襄 supplies the reading, drifting from xiāng to rǎng along an old initial alternation. The same phonetic surfaces in 让 (yield), 壤 (soil), and 攘 (push aside), all clustered around the rang and xiang syllables.
