truly, graciously, gratuitously, ravenously
叨 centers on receiving or taking something in a manner that is either humble and grateful (truly, graciously) or excessive and greedy (gratuitously, ravenously). The common thread is an action involving acceptance or consumption, with the tone ranging from polite to voracious.
叨 combines 口 (mouth) and 刀 (knife), suggesting a mouth receiving or taking something, possibly with a blade-like eagerness. The exact historical development is uncertain, but the components likely contribute to the ideas of speaking (graciously) or consuming (ravenously).
A mouth 口 beside a knife 刀: imagine someone speaking truly and graciously, or a mouth ravenously taking food as if cutting it with a knife.
For トウ, picture a person receiving a gift and saying "toe" as a humble, gracious thanks: toe -> トウ, tying the sound to the grateful acceptance meaning.