noisy
呶 centers on loud, disruptive sound: being noisy or clamorous. The single given meaning "noisy" captures the core idea of vocal commotion.
呶 combines 口 (mouth) with 奴, which likely contributes the sound. The exact historical development is uncertain, but the structure suggests a phono-semantic compound related to vocal noise.
A mouth 口 beside 奴 (which can suggest a servant or person) makes a noisy racket. Picture a servant shouting loudly through an open mouth.
For ド, imagine a noisy drum: the deep "do" sound of a drumbeat cues ド while the mouth 口 makes the noise.