This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
啑 combines 口 (mouth) with 疌, a component whose historical role here is uncertain. The exact development is unclear.
With 口 (mouth) on the left and 疌 on the right, imagine a mouth making a quick, indistinct sound, but the exact meaning is uncertain.
For ソウ, imagine a mouth making a soft 'sou' sound, like a gentle sigh: sou -> ソウ.
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