garrulous, to whisper, to joke
詀 centers on speech that is light, informal, or excessive: being garrulous, whispering, or joking. The common thread is casual or non-serious talk.
詀 combines 言 (speech) with 占, which likely contributes the sound. The exact historical development is uncertain, but the structure suggests a phono-semantic compound related to talking.
Words 言 that are like a fortune-teller's 占 chatter: light, whispered, or joking talk that fills the air.
For タン, imagine a tongue wagging with garrulous talk: tongue -> タン, and the 言 radical reinforces the speech.
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