loquacious, nag
囌 centers on excessive, persistent talking: being loquacious or nagging someone with words.
囌 combines 口 (mouth) with 蘇, which likely contributes the sound. The mouth radical suggests the meaning relates to speech.
The mouth 口 on the left and the complex 蘇 on the right suggest a mouth that keeps going and going, like a nagging voice that won't stop.
For ソ, imagine a nagging person saying 'so... so... so...' over and over: the repeated 'so' cues ソ while the mouth keeps talking.