roar
嚄 centers on a loud, forceful vocal outburst: a roar. It conveys a sudden, powerful cry or shout.
嚄 combines 口 (mouth) with 蒦, which likely contributes the sound and relates to capturing or measuring. The exact historical development is uncertain, but the mouth radical clearly indicates a vocal action.
The mouth 口 on the left and the complex 蒦 on the right suggest a mouth producing a loud, capturing sound: a roar that grabs attention.
For カク, imagine a loud roar echoing in a canyon: the sound 'cack' (カク) reverberates off the walls.